Dr. Porter is an independent investigative journalist and historian, the author of Manufactured Crisis: The Untold Story of the Iran Nuclear Scare (Just World Books, 2014). Porter has covered U.S. national-security issues for the Rome-based Inter Press Service since 2004. He is the 2012 recipient of the Gellhorn Prize for Journalism, awarded by the Gellhorn Trust in the UK in honor of American journalist Martha Gellhorn. His previous book was Perils of Dominance: Imbalance of Power and the Road to War in Vietnam (University of California Press, 2005).
The rockets that landed in the Damascus suburbs on August 21, 2013 — immediately regarded by the Obama administration and the news media as a nerve-gas attack — brought the United States to the brink of war with the Assad regime. President Barack Obama stepped back from launching cruise missiles only at the very last moment, August 30, according to the most detailed account of the episode.1
The presumption that the Syrian government had crossed Obama's "red line" against the use of chemical weapons was already full-blown: In mid-June 2013, the administration had announced an intelligence assessment affirming that the regime had used chemical weapons, including Sarin, several times over the previous year. This assessment was crucial in establishing a political climate within and outside the Obama administration that made it very difficult for the president to avoid treating the claims of a Sarin attack in August as a fact. But it was an allegation, the truth of which still had to be established.
A review of what is known about the June assessment and the alleged Sarin attacks shows that it was a major intelligence failure on the order of the Iraq WMD error. It failed to reflect accurately the evidence the administration said supported the overall conclusion. Moreover, it ignored substantial evidence indicating that the incidents in question did not involve Sarin or anything else that the United States recognized as a banned chemical weapon. Finally, the evidence of responsibility for the alleged Sarin attacks did not confirm the accusation that they were carried out by the Syrian government.
THE APRIL 2013 ASSESSMENT
The June 2013 intelligence assessment was preceded six weeks earlier by an intelligence assessment that appeared, on the surface at least, to endorse the view that Syria had used chemical weapons. However, it stopped short of doing so. The April 2013 assessment was carried out in the context of new international pressures on the Obama administration to accuse the Assad regime of chemical-weapons attacks. Letters from the British and French governments to UN Secretary General Ban Ki Moon in mid-March had claimed that evidence supported the opposition charge that nerve agents had been used in attacks near Aleppo, Homs and possibly the Damascus suburbs. It cited what the two governments said was conclusive evidence from soil samples and interviews with witnesses.2 U.S. allies, including those in the Middle East, were reportedly "irked" by the failure of the Obama administration to do more to assist the armed opposition to the Assad regime.3
Far from being disinterested parties on the questions at issue, however, the British and French governments were exploiting opposition charges of Sarin use to bolster their joint campaign to get the European Union to end its embargo on providing weapons to either side in the Syrian war.4 In mid-March, when the British and French launched their push to end the arms embargo — but before either government was claiming to have evidence of chemical-weapons use — French President François Hollande declared, "We must go further" to assist the Syrian rebels against the regime, because of "some potential threats as to the use of chemical weapons."5
In any case, the evidence that the two countries claimed to have was clearly inconclusive regarding what was used in the attacks and who was responsible. The soil samples did not prove that the substance was Sarin or another nerve gas. The Times reported on April 13 that the British Ministry of Defence research facility in Porton Down had found traces of what it called "some kind of chemical weapon" in the soil samples, which were said to have come from Khan al-Assal near Aleppo, the target of an alleged chemical-weapon attack on March 13. The researchers had determined that the chemical used in the attack wasn't Sarin, though they had been unable to identity it precisely, according to The Times.6
Obama administration officials further noted that it had not been established who had handled the samples before a laboratory had analyzed them. The Syrian government had immediately called for a UN investigation of what it claimed was a Sarin attack on the government-controlled enclave of Khan al-Assal, suggesting that it was carried out by opposition forces.7 But opposition commanders in the area had argued both that a government chemical-led shell had missed its target and that the government had deliberately attacked its own people to make the opposition look guilty. And the Obama administration, apparently recognizing that its position on the incident could not be separated from its need to reassure its allies on U.S. Syrian policy, had immediately rejected any possibility that the opposition could have carried out the attack on Khan al-Assal.8
On April 13, British Foreign Minister William Hague claimed to have "very strong evidence" that chemical weapons had been used in Syria. However, Hague made a damaging admission to Parliament: improvised chemical weapons may have been used by both sides — "by the regime to show that the opposition are using chemical weapons, and by the opposition to show that the regime is using them."9
Despite political pressure from U.S. allies for more aggressive U.S. military assistance to the opposition, the Obama administration was still guarding its freedom of action on the issue of intervening in the war. As the foreign ministers of the core group of the "Friends of Syria" (the United States and 11 other states supporting the opposition) met in Istanbul on April 20, a Turkish Foreign Ministry official explained to a journalist the main issue at the meeting: the Obama administration's continued resistance to the proposal from the two European governments and the Middle Eastern allies (Turkey, Saudi Arabia and Qatar) to step up the flow of arms to the opposition.10
The White House's presentation of the April intelligence assessment nevertheless sought to reassure allies that President Obama was taking the allegations of chemical-weapons use seriously. At a press briefing on April 25, an unidentified White House official announced that the intelligence community had concluded with "varying degrees of confidence" that the Assad regime "has used chemical weapons on a small scale in Syria, specifically the chemical agent Sarin," and that the assessment was "based in part on physiological samples." However, the official went on to say, "Our standard of evidence must build on these intelligence assessments as we seek to establish credible and corroborated facts. For example, the chain of custody is not clear, so we cannot confirm how the exposure occurred and under what conditions."11
The Obama administration also leaked to CBS News that the intelligence community had expressed only "low to moderate confidence" in the conclusion.12 According to the 2007 National Intelligence Estimate on the Iranian nuclear program, in the parlance of intelligence assessment, "low confidence" means that either there are serious concerns about sources or the information itself is implausible or can't be corroborated. "Moderate confidence" generally means that the information is credibly sourced and plausible but requires corroboration to be deemed sufficiently reliable.13 In other words, the claims at best still had to be verified, and at worst, they were regarded as lacking in credibility.
In a television interview, Defense Secretary Chuck Hagel said, "We still have some uncertainties about what was used, what kind of chemical was used, who used it." And a letter from White House aide Miguel Rodriguez to members of key Congressional committees made it clear that the assessment had not resolved fundamental questions. "Only credible and corroborative facts that provide us with some degree of certainty will guide our decision making," said the letter. 14
Under pressure from Congress and the media, as well as foreign allies, Obama approved a secret presidential "finding" authorizing the CIA to initiate a covert program to train and arm a small group of rebels loyal to the Western-backed "Supreme Military Council" in Turkey. The plan would involve moving weapons to Jordan with the cooperation of U.S. allies and then distributing them to a small set of selected Syrian rebel groups. This new overt program also included the establishment of two-week training courses in Jordan.
By agreeing only to a covert operation rather than a publicly acknowledged program, however, Obama was able to maintain the official stance that the United States was not involved in providing lethal military aid to the rebels. For the next two months, the covert program stalled, and no weapons were actually moved to the rebels.15
A "HIGH-CONFIDENCE" ASSESSMENT
A few weeks after the inconclusive intelligence assessment was announced, the intelligence community provided a new one that was presented to the public as accepting the chemical-weapons-attack claims without reservation. According to a statement issued by Deputy National Security Adviser Ben Rhodes, the assessment found that the Assad regime "has used chemical weapons, including the nerve agent sarin, on a small scale against the opposition multiple times in the last year." The intelligence community was said to have "high confidence" in the assessment, in sharp contrast to the obviously weak support offered in April.16
The claim of strong confidence in the assessment's conclusion seemed to suggest that the intelligence community now had much more conclusive evidence of chemical-weapons attacks. But the public record makes it clear that no such conclusive evidence was ever obtained. The information provided by the administration about the basis for the conclusion came entirely from a formal statement and press briefing by Rhodes and from an unpublished letter from UN Ambassador Susan Rice to UN Secretary General Ban-Ki Moon that was leaked to the Associated Press. Rhodes said that an estimated 100 to 150 people had been killed in alleged chemical attacks, but there was no accounting of where and when or even a total of how many such attacks were alleged.
Both the Rhodes statement and the Rice letter mentioned four incidents as being "associated with" the assessment, of which only two were said to involve the use of Sarin gas — Khan al-Assal on March 19 and the Sheikh Maqsood district of Aleppo city on April 13. The other two alleged chemical-weapons attacks to which the official statements referred were identified as Qasr Abu Samra on May 24 and Adra, near Damascus, on May 23. Rhodes and Rice provided no information about the kind of chemical weapon allegedly used in those two other attacks.
All known chemical weapons can be identified relatively easily, so the Obama administration's refusal to be more precise appears to have been aimed at covering up a political problem. A major clue can be found in a New York Times story in mid-April, just as British and French pressure on the administration to charge Assad with Sarin attacks was growing. The Times reported that the testimony of Director of National Intelligence James Clapper before the Senate Armed Services Committee "reflected a growing assessment within the American intelligence community that the Syrian government may have used some kinds of chemical agents, like a powerful tear gas, but not the most deadly ones, like sarin."17
The State Department had leaked to CNN that its investigation into the alleged Sarin attack on Homs in December 2012 had concluded that the chemical agent had been a "powerful riot-control gas" such as those used by U.S. forces for decades, including in the war in Iraq.18 The United States had consistently refused to consider riot-control agents as "chemical weapons," unlike every other state that had negotiated the chemical-weapons convention.19
But those were not the only weapons on the Syrian battlefield that the Obama administration was reluctant to acknowledge and discuss explicitly. As reviewed in detail below, there is overwhelming evidence that alleged Sarin attacks in April 2013 had involved smoke grenades, which can create symptoms similar to those caused by Sarin, but are much less lethal.20 Other signatories to the chemical-weapons convention would consider such weapons to be banned "chemical weapons." But the United States continues to manufacture and stock such weapons and would certainly argue, if forced to do so, that they are not "chemical weapons." It had strong motivation, therefore, to refuse to discuss them explicitly in the context of the Syrian chemical-weapons issue. This explains why the Obama administration would not say anything further about the chemical weapons other than Sarin that it was citing as part of its indictment of the Assad regime.
Neither Rhodes nor Rice claimed that the intelligence community now had what it had conspicuously lacked in April: physical evidence of a Sarin attack or any other genuine chemical-weapons attack for which the chain of custody could be verified.21 An intelligence source revealed to Foreign Policy that U.S. intelligence had possessed at least three physiological samples when it issued the inconclusive April assessment, and that it now had six blood, urine and hair samples testing positive for Sarin gas. But the source acknowledged that it still had not been able to establish the chain of custody for any of the samples.22
Khan al-Assal was one of the locations from which U.S. intelligence had obtained physical samples supposedly taken from victims, according to a New York Times report. The samples reportedly had tested positive for Sarin, but the U.S. official who confirmed that fact also said it had not been established precisely how, where and from whom they had been drawn.23 Furthermore, the final report of the UN investigating mission cast doubt on the physical samples it had obtained from Khan al Assal. The mission was able to take blood samples from two survivors of the attack whose DNA had been collected at the time and could be verified, and it found no traces in them of the signature of any chemical-warfare agent. Moreover, there was no evidence whatever that the Khan al-Assal attack had been carried out by the Assad regime. The UN mission observed that the village of Khan al-Assal was "under the control of Syrian Government forces on 19 March 2013," and that the village had been the object of ongoing shelling by opposition forces from areas surrounding it.24
Despite two trips to Turkey to interview doctors from Syria in late June and early July, the UN mission was unable to reach alleged witnesses or to obtain biomedical samples related to the April 13 Sheikh Maqsood incident. The UN team concluded that it couldn't corroborate the allegation that chemical weapons had been used there.25
Further evidence that the Sheikh Maqsood attack was probably not carried out by regime forces came from a report published by the Global Post later that month, shedding more light on the confused political situation surrounding the attack. The opposition sources said the Kurdish YPG, which controlled the Sheikh Maqsood neighborhood, had been allowing rebel forces to enter it to attack government forces — but had also been informing the government of the plans in advance. Less than two weeks after the alleged Sarin attack, the rebels accused the Kurds of "double-crossing" them, and a serious military clash between the YPG and the rebels killed several people.26
The alleged chemical-weapons attack on Adra, reported by opposition "campaigners" on May 23, was said to have taken place when opposition troops were surrounding the town, which was under Syrian government control. The opposition reported that the gas attack killed one opposition fighter and wounded 23.27 No press report on any alleged chemical attack at Qasr Abu Samra can be found. Despite Ben Rhodes's claim that the United States was seeking to provide evidence to the UN mission investigating alleged chemical attacks, the mission's final report noted that it had not been given "sufficient or credible information" about those two alleged incidents to merit further investigation.28 A complete list of alleged chemical-weapons attacks up to the time the June assessment was released does not mention one in Qasr Abu Samra.29
IGNORING CONTRARY EVIDENCE
The June assessment ignored an important new stream of information that became available after the April 25 assessment for determining what had actually happened in the alleged chemical-weapons incidents. The new information pointed clearly to the conclusion that the Sheikh Maqsood attack, cited by both Rhodes and Rice as evidence of Sarin use by the Assad regime, almost certainly did not involve Sarin or any other chemical weapon in the common usage of the term — and was probably not carried out by the Assad regime.
On April 29, immediately after the alleged chemical-weapons attack on Saraqeb, British blogger Eliot Higgins, who was systematically tracking munitions in the Syrian war under the name "Brown Moses," published a series of photos showing that the same means were used in both that attack and the April 13 attack on Sheikh Maqsood.30 The delivery vehicle was a tiny white polymer canister, the body of which was little more than three inches high, with a lid and "fly off" lever. A close-up video showed that it had four holes distributed evenly around its surface.31
The new stream of information also showed that al-Nusra Front and other opposition troops were definitely in possession of that type of canister. On May 8, the website published a photograph of the same plastic canister hanging from the jacket of a Nusra Front fighter in the Aleppo area. 32 The photographer, Jeff Ruigendijk, recalled in an e-mail to this writer that he had taken the picture on April 2, 2013 — eleven days before the Sheikh Maqsood attack — and that the Nusra Front cadre carrying it was not a military specialist but a low-level functionary whose task was to sort out the lines at the bakery every morning.33
Journalist Alfred Hackensberger of Die Welt visited the fighting front in and around Aleppo during the summer of 2013 and talked with two Nusra Front fighters who recalled seeing the same canisters being carried by rebel troops, although they weren't sure whether they were from Nusra Front or their allies Liwa al-Tawhid. They confirmed to Hackensberger that the munitions were smoke grenades, not chemical weapons. In Aleppo, Hackensberger found two more Nusra Front fighters who recognized the canister and showed him and his photographer other canisters of the same type. They, too, told Hackensberger they were smoke grenades, and that they came from Syrian Army depots that Nusra Front had captured.34
The Brown Moses blog published interviews with two experts on chemical weapons who agreed that it was highly unlikely the canister shown in the pictures from those attacks had been used to deliver Sarin gas or any other deadly chemical weapon.35 Steve Johnson, the deputy editor of CBRNe, the bimonthly periodical for professionals on chemical, biological and nuclear weapons, observed that the device had no "fragmentation jacket" and was therefore most likely a grenade for delivery of riot-control gas or smoke. The Nusra Front fighter carrying the canister in Ruigendijk's photo wore no protective equipment — meaning that it was not a chemical weapon.
A chemical-weapons expert from the security consulting firm Allen Vanguard, identified only as "Paul," observed that Sarin is "not suited to being deployed in hand-thrown canisters;" as doing so would obviously endanger the person delivering it. He also noted that Sarin "would not leave marks next to the hole in the canister as shown in the image," whereas a smoke grenade would.
In the case of Saraqeb, the implausibility of a Sarin attack was further magnified by the account provided to the UN investigating mission by an opposition figure who was their main source on the incident. The final report recalls that a "source close to the opposition" provided an account of the attack evidently seeking to prove it was carried out by the Syrian government. The source claimed that the tiny gas grenade had been dropped from a helicopter using a cement cinder block with round holes. The source said the cinder block had served to "secure" the small hand grenade from exploding until it hit the ground, upon which the handles of the grenades would become activated and discharge. The source further claimed that some of the canisters contained tear gas, whereas others contained Sarin.
However, the source's story, which appears to have been an effort to show that the tiny white canister found on the scene must have been delivered by the regime rather than by opposition troops, was not supported by any visual or other evidence. It describes a highly implausible method of delivering any chemical weapon, much less Sarin. The UN mission's final report observed that the information from the opposition source about the Saraqeb attack "could not be independently verified by the United Nations Mission."36
Eyewitness accounts in news reports of the Sheikh Maqsood and Saraqeb attacks provide still more evidence that the chemical used in the two attacks was not Sarin. After the Sheikh Maqsood attack, neighbors who entered the home in which two children died described "smelling a sharp, bitter odor that stung their eyes."37 Similarly, after the April 29 Saraqeb attack, which appears to have been very similar to the Sheikh Maqsood attack, the son of the woman who died recalled, "It was a horrifying, suffocating smell."38 Sarin, by contrast, is an essentially odorless gas.39
THE MISSING PIECES
The series of anomalies for which the June 2013 intelligence assessment failed to account should have raised serious doubts about the claims of the opposition and their external supporters that the regime had used Sarin in Khan al-Assal and Sheikh Maqsood. In neither of those two cases was the regime seeking to take control of the area. In one case, it was clearly under attack from opposition forces at the time; in the other case, there is evidence of serious tension between the Kurdish authorities and the opposition forces in the area at the time of the attack. The delivery vehicle found in both places made a Sarin attack implausible, and the specific delivery vehicle used in both cases was clearly in the possession of opposition forces. Finally, the foul odor eyewitnesses had reported was inconsistent with Sarin gas, and the only physical samples reported whose chain of custody could be verified tested negative for Sarin.
Against these indications that the assessment's conclusion was false, defenders of the assessment could cite the set of reported symptoms that coincide with those for Sarin exposure and the fact that some physical samples from one or more attacks tested positive for Sarin. But an alternative explanation for the symptoms is more consistent with other evidence, and the claim of positive test results for Sarin does not prove that Sarin was used in either of the cases cited by Rhodes and Rice.
The symptoms reported by survivors and eyewitnesses — blurred vision, difficulty breathing, foaming at the mouth, nausea, vomiting, loss of consciousness, and convulsions — are not unique to exposure to Sarin. They are also consistent with exposure to conventional smoke munitions, which produce highly toxic phosphine gas when they make contact with the moisture in the air, causing symptoms like those associated with Sarin.40 Exposure to both gases involves severe damage to the body's ability to produce cholinesterase; this causes neurological symptoms, including convulsions.41
The evidence surrounding the canisters involved in the attacks on Sheikh Maqsood and Saraqeb, moreover, indicates that they were apparently used to dispense smoke. Such use of smoke munitions would account for the symptoms reported in both cases as well as the serious anomalies in the assessment that Sarin gas was used in those two attacks. The U.S. military and other militaries have long stocked grenades and mortars firing red-phosphorus munitions that form highly toxic phosphine gas upon contact with moisture in the air.42 Exposure to phosphine gas can cause unconsciousness, blurred vision, nausea, vomiting, difficulty breathing, fainting, convulsions and even pulmonary edema — just as does exposure to Sarin. And because it is heavier than air, it may cause asphyxiation and death in enclosed, poorly ventilated or low-lying areas, as does Sarin.43 The descriptions of the foul odors accompanying the attacks on Sheikh Maqsood and Saraqeb also indicate the presence of phosphine gas, which has an odor of rotting fish or garlic.44
The Obama administration provided no information about what criterion was used by the intelligence community in determining that it had evidence of Sarin exposure in either the Khan al Assal or Sheikh Maqsood cases. But the final report of the UN mission states that a physical sample was "considered positive when either the Sarin metabolite isopropyl methylphosphonate (iPMPA) or the fluoride reactivation product of IMPA (Sarin) is detected at three times above base-line level." This means that a positive result of either of two very different tests would be considered evidence of exposure to Sarin.
For many years the only test of blood, urine or tissue for Sarin exposure was based on the detection of the Sarin metabolite breakdown product, designated as either iPMPA or IMPA through gas or liquid chromatography and mass spectrometry. This is because Sarin itself begins to break down in the body within hours and because IMPA is considered a reliable marker of Sarin exposure.45 But IMPA is easily obtainable from any chemical company as a "reference" material for research and could be administered to the source of a blood or urine sample unobtrusively in a glass of water without any threat of harm to health. In fact, 300 parts per million of IMPA in drinking water for 90 days is officially regarded as a "no effects" level.46 Thus the opposition could, without being detected, have falsified one or more physical samples that were ultimately obtained by the U.S. government.
More recently, new technologies using "fluoride reactivation" have made it possible to reconstitute Sarin itself even after it has broken down.47 The newer tests would obviate the possibility of a false positive through introduction of IMPA into the body of the source of the sample. But if the rule adopted by the UN mission that a positive for either IMPA or Sarin itself was also used by the Obama administration, the possibility of falsified physical evidence of Sarin exposure remains.
That possibility would explain why some within the Obama administration were suspicious of physical samples that had tested positive for Sarin. Those officials believed the opposition, well aware of Obama's "red line" on chemical weapons as a potential route to drawing the United States into the war against Assad, was motivated to "falsify" the samples that found their way into French government hands. The combination of the motive and the technical possibility of cheating is presumably why the Obama administration had raised the issue of the "chain of custody" in April as a problem that had to be settled before a conclusion could be reached on the issue. In June, however, as the political calculations of the White House shifted, the administration chose to ignore that problem in presenting the revised intelligence assessment.
POLICY, POLITICS AND INTELLIGENCE
The glaring weaknesses of the case for accusing the Assad regime of a series of chemical-weapons attacks in spring 2013 pose an obvious question: Why did the Obama administration embrace that assessment so enthusiastically in June — after having insisted on much more conclusive evidence in April? The answer appears to be the perceived need to support a policy shift in Syria with which the assessment had become tightly linked. During the weeks prior to the June assessment, the heavy pressure from foreign allies and domestic critics to begin a serious program of assisting the anti-Assad armed opposition intensified. So did the demand that the United States support the accusation that Assad had used chemical weapons. The Obama White House was evidently not convinced the line had been crossed in April, and the intelligence community had delivered an assessment supporting the need for corroborative evidence. But, as the White House contemplated the acceptance of a more active program of assistance to the armed opposition, its position on the issue of chemical weapons shifted as well.
In fact, the linkage between the two issues had become a simple problem of political messaging. The administration did not believe it could present itself as the champion of the anti-Assad forces while at the same time resisting the argument of the opposition and its external supporters that Assad had used chemical weapons. When Deputy National Security Adviser Rhodes briefed the news media on June 13, he said the administration had "already taken action" on "both the scale and type of support that we're providing to the opposition" and explained it as a consequence of the new intelligence assessment. "We now have a high-confidence assessment that chemical weapons have been used on a small scale by the Assad regime," said Rhodes. "And so he [the president] has said that the use of chemical weapons would change his calculus, and it has. Since April, as we've reviewed this evidence, we have increased our support and provision of assistance to the opposition."48
The evidence clearly shows, however, that Obama agreed to announce military aid to the anti-Assad forces, not because of new evidence of chemical-weapons use, but because both Obama's senior advisers and the rebel commanders were warning that Assad's military was threatening to wrap up the armed opposition.
The primary motive driving Obama's decision making at that point was apparently the fear that the entire anti-Assad war could collapse and hand a victory to Assad's Iranian allies — and that he would be blamed for it. A series of high-level meetings were hastily organized in the wake of the recapture of the town of Qusayr by a combined force of Syrian-government and Hezbollah troops on June 5 after a bloody two-week battle in the single biggest defeat for the rebels up to that time.49 Just before the rebels retreated from Qusayr, a Syrian rebel commander warned in an "emergency phone call" at the end of the week of June 3, 2013, that a combined Syrian-government-Hezbollah military force gathering around Aleppo was threatening to eliminate the armed opposition's military presence in that strategic city. A source familiar with the internal discussion recalled that Secretary of State John Kerry had warned in a meeting between Obama and his senior advisers that, unless he agreed to step up support for the anti-Assad forces, regional "partners" would withdraw their support for the rebels, threatening a complete collapse of the entire anti-Assad effort.50 Gulf Arab commentators were treating the victory of Syrian-Hezbollah forces as a tipping point for Iranian dominance in the entire region, and the Washington Post's coverage adopted that viewpoint.51
The administration's policy making and the accompanying intelligence assessment on Syria in June 2013 thus dramatically illustrate the strong aversion of officials to revealing the actual facts surrounding an issue when those facts conflict with policy decisions they regard as politically necessary. This analysis of the June 2013 intelligence assessment shows that arriving at an intelligence assessment in conjunction with major policy issues tends to be a quintessentially political process.
1 Jeffrey Goldberg, "The Obama Doctrine," The Atlantic, April 2016, http://www.theatlantic.com/magazine/archive/2016/04/the-obama-doctrine/….
2 Colum Lynch and Karen DeYoung, "Britain, France Claim Syria Used Chemical Weapons," Washington Post, April 18, 2013.
3 Karen DeYoung, "U.S. Reluctance to Aid Rebels Irks Allies," Washington Post, March 17, 2013.
4 Steven Erlanger, "Seeking to Arm Rebels in Syria, France Urges End to Arms Embargo," New York Times, March 15, 2013.
5 Charlotte McDonald-Gibson, "François Hollande Tells EU: It's Time to Send Arms to Syrian Rebels," The Independent (London), March 14 2013.
6 Michael Evans, "Chemical Weapons Used in Syria: The First Evidence," The Times (London), April 13, 2013, http://www.thetimes.co.uk/tto/news/world/middleeast/article3738391.ece.
7 "Secretary-General's Press Encounter on Syrian Government Request," United Nations, March 21, 2013, http://www.un.org/sg/offthecuff/index.asp?nid=2745.
8 "Syria Rebels, Regime Blame Each Other for First Alleged Chemical Weapons Attack," CBS News, March 19, 2013; and "Press Briefing by Press Secretary Jay Carney, 3/19/2013," https://www.whitehouse.gov/the-press-office/2013/03/19/press-briefing-p….
9 "Evidence of Nerve Gas in Aleppo Deaths," ABC News, April 17, 2013, http://abcnews.go.com/International/evidence-nerve-gas-aleppo-deaths/st….
10 Tulin Daloglu, "Friends of Syria Deliver Nothing New," Turkey Pulse, al-Monitor, April 21, 2013, http://www.al-monitor.com/pulse/originals/2013/04/syrian-opposition-rad….
11 "Background Conference Call by White House Official on Syria," April 25, 2013, https://www.whitehouse.gov/the-press-office/2013/04/25/background-confe….
12 "Syria Has Likely Used Chemical Weapons on a 'Small Scale', Chuck Hagel Says," CBS News, April 25, 2013, http://www.cbsnews.com/news/syria-has-likely-used-chemical-weapons-on-a….
13 "Iran: Nuclear Intentions and Capabilities," National Intelligence Estimate, Office of Director National Intelligence, November 2007, https://www.dni.gov/files/documents/Newsroom/Reports%20and%20Pubs/20071….
14 "Syria Has Likely Used Chemical Weapons on a 'Small Scale'..." CBS News, April 25, 2013.
15 Mark Mazzetti, Robert F. Worth and Michael R. Gordon, "Obama's Uncertain Path Amid Syria Bloodshed," New York Times, October 23, 2013, http://www.nytimes.com/2013/10/23/world/middleeast/obamas-namncertain-p….
16 "Statement by Deputy National Security Advisor for Strategic Communications Ben Rhodes on Syrian Chemical Weapons Use," June 13, 2013, https://www.whitehouse.gov/the-press-office/2013/06/13/statement-deputy…-.
17 Rich Gladstone and Eric Schmitt, "Syria Faces New Claim on Chemical Arms," New York Times, April 18, 2013.
18 Elise Labott, "U.S.: Syria Didn't Use Chemical Weapons in Homs Incident," CNN, January 16, 2013.
19 Roman Reyhani, "The Legality of the Use of White Phosphorus by the U.S. Military during the 2004 Fallujah Assaults," University of Pennsylvania Journal of Law and Social Change 10 (2007), 16-19. http://scholarship.law.upenn.edu/cgi/viewcontent.cgi?article=1065&conte….
20 See notes 29-33.
21 "Statement by Deputy National Security Advisor for Strategic Communications Ben Rhodes on Syrian Chemical Weapons Use"; "On-the-Record Conference Call by Deputy National Security Advisor for Strategic Communications Ben Rhodes on Syria," https://www.whitehouse.gov/the-press-office/2013/06/13/record-conferenc…; and Edith Lederer, "U.S. Letter: Syrian Regime Used Sarin Twice in Aleppo," Yahoo News , June 14, 2013, http://www.cnsnews.com/news/article/us-letter-syria-regime-used-sarin-t….
22 Noah Shachtman and John Hudson, "Source: U.S. Couldn't Nail Down Chemical Weapons Chain of Custody," The Cable, Foreign Policy, June 14, 2013.
23 Karim Faheem, "Still More Questions than Answers on Nerve Gas in Syria," New York Times, June 10, 2013, http://www.nytimes.com/2013/06/11/world/middleeast/still-more-questions….
24 United Nations Mission to Investigate Allegations of the Use of Chemical Weapons in the Syrian Arab Republic, Final Report, December 12, 2013, pp. 30-4, https://unoda-web.s3.amazonaws.com/wp-content/uploads/2013/12/report.pdf.
25 Ibid., 79.
26 Tracey Shelton and Peter Gelling, "Syria: Rebels and Kurds clash in Aleppo," Global Post, April 26, 2013, http://www.globalpost.com/dispatch/news/regions/middle-east/syria/13042….
27 "Syria Chemical Weapons: Opposition Says Syrian Forces Fired Chemical Weapons at Rebels in Town of Adra," Reuters, May 24, 2013.
28 United Nations Mission to Investigate Allegations of the Use of Chemical Weapons in the Syrian Arab Republic, Final Report, p. 10.
29A New Normal: Ongoing Chemical Attacks in Syria (Syrian-American Medical Society, 2016), 56.
30 "Links between Alleged Chemical Attacks in Saraqeb, Idlib and Sheikh Maghsoud, Aleppo," Brown Moses Blog, April 29, 2013, http://brown-moses.blogspot.co.uk/2013/04/links-between-alleged-chemica….
32 "Jabhat al Nusra with 'Chemical Weapons'," Ruig Photography website, May 8, 2013, http://www.ruigphotography.com/NusraChemicalWeaponsSyria.
33 E-mail to the author from Jeff Ruigendijk, September 5, 2013.
34 Alfred Hackensberger, "Die Beweise für den Einsatz von Giftgas sind dünn" [The evidence for the use of poison gas is thin], Die Welt (Hamburg), July 8, 2013, http://www.welt.de/politik/ausland/article117881245/Die-Beweise-fuer-de….
35 "Three Chemical Weapons Specialist [sic] Answer Questions about Chemical Weapons in Syria," Brown Moses Blog, May 21, 2013, http://brown-moses.blogspot.com/2013/05/three-chemical-weapon-specialis….
36 United Nations Mission to Investigate Allegations of the Use of Chemical Weapons in the Syrian Arab Republic: Final Report, December 2013, pp. 35-36.
37 Mohammed Sergie and Karen Leigh, "Evidence of Nerve Gas in Aleppo Deaths," ABC News, April 17, 2013, https://gma.yahoo.com/evidence-nerve-gas-aleppo-deaths-160842635.html.
38 "BBC Shown 'Signs of Chemical Attack," BBC, May 18, 2013, http://www.bbc.com/news/world-middle-east-22549861.
39 "Facts about Sarin," Center for Disease Control and Prevention, Emergency Preparedness and Response, http://emergency.cdc.gov/agent/sarin/basics/facts.asp.
40Operator's and Organizational Maintenance Manual for Grenades (Headquarters, U.S. Army, 1986).
41 Nisa S. Nath, Ishita Bhattacharya, Andrew G. Tuck, David I. Schlipalius, and Paul R. Ebert, "Mechanisms of Phosphine Toxicity," Journal of Toxicology (2011), http://www.hindawi.com/journals/jt/2011/494168/; and M. W. Abu-Qare and M. B. Abou-Donia, "Sarin: Health Effects, Metabolism and Methods of Analysis," Food Chemistry Toxicology 40, no. 10 (2002): 1327-33, http://www.ncbi.nlm.nih.gov/pubmed/12387297.
42 Committee on Toxicity, National Research Council, Toxicity of Military Smokes and Obscurants, vol. 1 (National Academies Press, 1997), 98-100; Jane's Ammunition Handbook, 2008-2009, (17th ed.), eds. Lionel Ness and Anthony G. Williams (Jane's Information Group Limited, 2008), 506.
43 National Institute for Occupational Safety and Health (NIOSH), "Phosphine: Lung Damaging Agent," http://www.cdc.gov/niosh/ershdb/emergencyresponsecard_29750035.html.
44 Health Protection Agency (UK), "Phosphine General Information," https://www.gov.uk/government/uploads/system/uploads/attachment_data/fi….
45 Ian Sample, "Syrian Chemical Weapons: How Lab Tests Uncover Evidence of Sarin Gas," The Guardian, September 5, 2013, https://www.theguardian.com/world/2013/sep/05/syrian-chemical-weapons-t…; and Helen Carmichael, "French Convinced Sarin Used in Syria," Chemistry World, June 11, 2013, http://www.rsc.org/chemistryworld/2013/06/french-sarin-detection-syria.
46 Sylvia S. Talmage et al, "The Fate of Chemical Warfare Agents in the Environment," in Chemical Warfare Agents: Toxicology and Treatment, eds. Timothy T. Marrs, Robert L. Maynard and Frederick Sidell, 2nd ed. (John Wiley & Sons, 2007), 110.
47 Jin Young Lee and Yong Han Lee, "Improvements to the Fluoride Reactivation Method by Simple Organic Extraction for Retrospective Detection of Exposure to the Organophosphorus Nerve Agents in Human Plasma," International Journal of Analytical Mass Spectrometry and Chromatography 2, no 3 (September 2014): 65-76, http://file.scirp.org/pdf/IJAMSC_2014092511194065.pdf.
48 "On-the-Record Conference Call by Deputy National Security Advisor for Strategic Communications Ben Rhodes on Syria," June 13, 2013.
49 Mark Mazzetti, Micharl R. Gordon and Mark Landler, "U.S. Is Said to Plan to Send Weapons to Syrian Rebels," New York Times, June 14, 2013.
50 Adam Entous, "Behind Obama's About-face on Syria," Wall Street Journal, June 15, 2013.
51 Liz Sly, "Iran on Ascent as Syria Churns," Washington Post, June 12, 2013, A1.