In 2012, a year into the Syrian civil war, U.S. president Barack Obama and British prime minister David Cameron became increasingly concerned about Syria's large chemical weapons arsenal. They feared President Bashar Assad might use his weapons internally, transfer them to a third party, or lose control of them altogether. In August of that year, President Obama made his now famous "red line" statement, warning of "enormous consequences" if Assad were to use them. Cameron and other Western leaders publicly seconded Obama's warning.
Later that year, reports of small-scale use of chemical weapons trickled in. The West failed to respond, and in August 2013, the regime launched a major attack on the Ghouta area east of Damascus, killing more than 1,400 people. A U.S.-led military operation against Syria's chemical weapons facilities seemed likely, and there were good reasons to believe that Britain would support its transatlantic ally in holding Assad to account and seeking to deter future chemical use. Yet events took an unexpected turn when Cameron—heading up a Conservative-Liberal coalition government—brought the matter to a vote in the House of Commons and lost, undermining the broader Western position and contributing to Obama's decision to refrain from launching punitive strikes.
Since the end of the Cold War, London had stood side by side with Washington against the proliferation and use of weapons of mass destruction (WMD) in the Middle East and North Africa. From the disarmament of Saddam Hussein's Iraq following the 1991 Kuwait war to the more recent Iranian nuclear threat, Conservative and Labour governments alike had been dependable partners for successive U.S. administrations. The events of August 21-29, 2013, appeared to represent something of a break with this trend. So what explains this rupture?
Washington and London's post-Cold War collaboration on counter-proliferation has been sustained and bipartisan on both sides of the Atlantic. Working together, the two allies disarmed the Saddam regime over a period of twelve years. They provided significant support to U.N. inspectors during the 1990s, and in 1998, the joint Operation Desert Fox struck Iraqi targets with airstrikes for four days.
Washington and London's post-Cold War collaboration on counter-proliferation has been sustained and bipartisan.
Later, during the 2002-03 run-up to the invasion of Iraq, British prime minister Tony Blair and U.S. president George W. Bush made the case together for unseating the Iraqi dictator on the grounds that his regime continued to develop and conceal its WMD capabilities. The intervention was ultimately discredited largely because of faulty intelligence, and the experience made the British public and their representatives in Parliament increasingly cautious and vocal about why and how armed force should be used to protect Britain's security interests.
The U.S.-led invasion of Iraq clearly marked a low point, but Libya's subsequent decision to forego its WMD programs in December 2003 was a win. Washington and London also worked closely together to reveal that Pakistan's A.Q. Khan network was supplying Libya's Mu'ammar Qaddafi with materials and components for uranium enrichment, and the two Western countries worked in tandem to remove those materials.
The Blair, Brown, and Cameron governments also worked with the Bush and Obama administrations to constrain Iran's nuclear ambitions by imposing a series of U.N. Security Council resolutions, some of which included a range of escalatory sanctions measures.
Based on this long-standing cooperation, it was reasonable to assume Britain would join the United States in acting against Assad following the Ghouta attack. So why did it not?
Chemical Weapons Crisis, 2012-13
In August 2012, Obama declared,
A red line for us is we start seeing a whole bunch of chemical weapons moving around or being utilized. That would change my calculus. That would change my equation.
A month earlier, Washington had received reports that the Assad regime was "preparing to use chemical weapons against the opposition, or transfer them to the terrorist organization Hezbollah." And while the prospect of Assad attacking his own citizens with chemicals had not figured prominently in U.S. thinking prior to this point—Syria's chemical arsenal had generally been viewed as a strategic deterrent against Israel—the possibility that the regime would lose control of these arms or transfer them to external actors had concerned the Obama administration since the early days of the conflict. No doubt, that was on the president's mind when his unscripted remarks later dominated coverage of his response to the Syrian conflict.
When Cameron spoke to Obama on a telephone call, they agreed that the use of chemical weapons was "completely unacceptable" and that would "force them to revisit their approach so far." The Western position was bolstered further by French president François Hollande, who drew his own red line and said that deploying chemical weapons was a "legitimate cause for direct intervention."As allegations of Syrian chemical weapons attacks gained momentum, Cameron doubled down. In April 2013, he said,
There is growing evidence ... of the use of chemical weapons, probably by the regime. It's extremely serious, this is a war crime ... I think what President Obama said was absolutely right. This should form, for the international community, a red line for us to do more.
During this period, Britain coordinated closely with its French and U.S. allies as they sought to determine where and how chemical weapons were actually being used. It was no easy task. The scale and source of the attacks were not yet clear. In hindsight, it appears that the Assad regime hoped to terrorize the opposition while maintaining plausible deniability. Using small-scale, primitive munitions meant that early attacks were difficult to attribute, and falsely accusing the opposition of using the weapons convinced enough people to prevent a united, determined response to Assad.
The major sarin attack on rebel-held Ghouta brought the issue to a head on August 21, 2013. The death toll was far higher than from any prior chemical weapons attack in the conflict, breaking with the pattern of small-scale use and suggesting that Assad's forces had tossed caution over the side. From a Western perspective, the Ghouta attack fundamentally changed the equation. Gen. Martin Dempsey, chairman of the U.S. Joint Chiefs of Staff, described the situation this way:
Militarily, his force has been at war now for two years. It is tired. They were having an extraordinary difficult time clearing neighborhoods because of apartment complexes and so forth. It consumes a military force to clear an urban setting. And so he took the decision to clear it using chemicals.
Responding to the Ghouta Attack
The Ghouta attack was such a flagrant breach of the U.S. red line that it could not be ignored or tolerated as previous attacks had been. For many observers, Washington's credibility was on the line, and failure to act would have implications for U.S. power and influence not only in Syria but elsewhere. In the week or so after the attack, senior U.S. officials signaled that a punitive military strike was now on the table. Mere days after the attack, Secretary of Defense Chuck Hagel said the United States had "moved assets in place to be able to fulfill and comply with whatever option the president wishes to take" and told reporters that U.S. military forces in the vicinity were "ready to go."
As Washington edged toward confrontation, Prime Minister Cameron seemed firmly aligned with the Obama administration's position. The two leaders agreed that Assad's escalation merited a "serious response," and a Downing Street spokesperson said that both had "tasked officials to examine all the options." Cameron later wrote,
Obama said he was considering a brief surgical "punish and deter" attack, and would like Britain to be part of it. Indeed, he actually said that only Britain really had the capabilities to make a difference, like submarine-launched Cruise missiles. We might be taking action within thirty-six hours, he said. Was I with him? I said yes.
The prime minister reiterated his "commitment to act in lockstep with the United States" in conversations between British foreign secretary William Hague and U.S. secretary of state John Kerry. Then on August 27, media reports described how French and British officials were working with the U.S. administration on plans for missile strikes on Syrian military targets.
Cameron became the first British prime minister to lose a vote on military action in more than a hundred years.
Just when the stage seemed set, however, there was a dramatic turn of events. Shortly after noon on August 27, Cameron announced that Parliament would be recalled from its summer recess for a vote on how to proceed, setting in motion a sequence of events that ultimately led to the decision to abstain from any military intervention linked to the Ghouta attack. Indeed, Cameron became the first prime minister to lose a vote on military action in more than a hundred years. The 285-272 vote shocked Washington and significantly influenced Obama's decision to seek congressional authorization himself. The Russians then proposed a disarmament initiative, removing the short-term prospect of military intervention and placing Syria's huge declared chemical weapons stocks on the table for destruction.
What then explains how Britain came to this position?
Cameron's Turn to Parliament
Obama's own hesitation arguably influenced the British response (or lack thereof) more than anything else. If the Obama administration had moved swiftly, Cameron could have justified British involvement as necessary in an emergency. But with each day of delay, Cameron had less room to maneuver.
By most accounts, Obama had been very close to ordering a military strike, but the presence in Syria of chemical weapons investigators from the United Nations caused a delay. The U.N. team had arrived in Syria on August 18. It was not there to seek an indictment. Rather, it was there to determine whether or not chemical weapons had been used prior to the Ghouta attack. In her memoirs, Samantha Power, then-U.S. ambassador to the U.N., writes,
The presence of the UN team caused Obama to delay the US military operation he hoped to launch on the night of August 25th. Every day for the next five days, Obama would ask me, Susan [Rice] or John Kerry, whether Ban [Ki-Moon] had withdrawn the flawed mission, so that he could order the planned strikes. And each day, one of us would report to the President that the UN investigators remained in Damascus. Obama was seething with frustration.
It was not until August 30, the day after the House of Commons vote, that the U.N. secretary general told the Obama administration that his team had found "convincing proof that sarin gas had been used" at Ghouta and that they would be leaving the next morning.
During the days following the Ghouta attack, Downing Street received little information as the White House weighed its options. Cameron had been willing to support a rapid U.S. response, but he found himself in a difficult position as the U.S. timetable slipped. While nobody doubted the likelihood of a U.S. strike, Cameron felt that he could not avoid putting the issue before Parliament.
The legacy of the 2003 invasion of Iraq weighed heavily on him, as did the rising expectation that Parliament ought to be consulted on questions of war and peace. Prime Minister Blair had consulted Parliament, after all, before deploying British forces in Iraq, and it was "the first example in modern times of prior parliamentary approval having been sought and granted" for military action. As such, it was "regarded by advocates of a formal role for Parliament as setting a precedent for any future decisions on military action." Blair made his decision to seek parliamentary support in part because the U.N. Security Council had not provided its own mandate, making the decision extremely controversial in Britain.
In the years after the 2003 vote, "several attempts to capitalize on the decision to allow that vote and give Parliament a formal, statutory-based, role were made." None resulted in legislation, yet the earlier vote had set a precedent, one that had been upheld before the NATO intervention in Libya in 2011. This time, Cameron was quick to announce that Parliament would have a vote even if it came two days after British military action had already been initiated. It helped that the U.N. Security Council had passed Resolution 1973 authorizing all necessary measures to protect civilians. This, combined with the involvement of NATO, left Cameron confident of Parliament's support.
Stepping Back from Military Action
In Syria, Cameron likely would have preferred to act quickly in concert with the United States and seek parliamentary approval shortly after initiating military action as he had done in Libya. At first, he resisted pressure to recall Parliament for a vote, but by August 27, "the pressure on the Prime Minister became intense" due to a combination of U.S. inaction and the perceived weight of an important emerging parliamentary convention. In any case, once he agreed to put the issue to a vote, he could not control the outcome. Despite efforts to rally support, the House of Commons said no.
Unlike with Libya in 2011, there was no prospect of a U.N. resolution backing military action in Syria.
The flawed process that had led to the invasion of Iraq in 2003 cast a long shadow. Several members of Parliament (MPs) questioned the strength of the evidence and insisted on first receiving support from the Security Council. Unlike with Libya in 2011, there was no prospect of a U.N. resolution backing military action in Syria. The Russians were unwilling to support such a resolution; they felt betrayed after the Libya intervention led to the overthrow of Qaddafi. Any action that could potentially lead to regime change in Syria, the Kremlin's most important ally in the region, would never be countenanced by Russian president Vladimir Putin.
Meanwhile, the Labour Party opposition was in no mood to support the government. Cameron and his team held intense discussions with the Labour leadership ahead of the vote and even expanded the original government motion to accommodate opposition concerns, but Labour Party leader Ed Miliband would not budge.
Finally, the British government motion was undermined by a perceived lack of clarity and forethought about the objectives and outcomes. MPs expressed a range of concerns, from doubts regarding the ability of air strikes to deter Assad to the lack of a "clear strategy for managing a military campaign" and the associated potential for "mission creep." The prime minister carefully emphasized the limited nature of the intervention, but MPs argued that it could "lead to all sorts of consequences that we have not perceived at this point." There was also a distinct lack of public appetite for military action, a point frequently made by MPs during the debate.[28
The British media castigated Cameron for his naivety, lack of foresight, and failure to appreciate the legacy of the Iraq invasion.
The British media castigated Cameron for his naivety, lack of foresight, and failure to appreciate the legacy of the Iraq invasion and the strength of opposition among both citizens and MPs. Fraser Nelson, writing in the Spectator, summed up the confluence of factors that helped thwart the prime minister's plans:
A third of the Tory party is opposed to a Syria strike; the public is against it by a ratio of two-to-one. And yet still, the Prime Minister of a hung parliament tries to ram through a vote for military action using the same methods and logic as Iraq ... And a Defence Secretary who went on Newsnight and actually spoke about taking action against "Saddam" rather than Bashar Assad. The whole thing looked like an Iraqi Ground-hog Day.
The outcome humiliated Cameron. "By one reckoning, this was the first time a British prime minister had seen his war plans foiled by parliament since 1782." It affected the future direction of his premiership. As well as making him more vulnerable in the House of Commons, it also seemed to mark the end of his
activist phase ... which, when the Libya intervention appeared to have been successful, was riding high. From now on, he will be much more of a cautious prime minister when it comes to foreign intervention.
But what was the significance on the international stage? It presented a major obstacle to a broader international response and directly influenced President Obama's decision to seek legislative authorization for U.S. action. Yet the impact of all this on U.S.-British counter-proliferation cooperation should not be exaggerated. Three points are worth noting here.
First, the same factors that shaped the course of events in Britain resonated strongly in the United States. The Obama administration grappled with them before and after the British vote. The president was clearly unenthusiastic about military engagement in Syria. Indeed, much of the commentary during that time focused on his obvious reluctance to enforce his own red line.
Second, Cameron was prepared to authorize British involvement but felt he had no choice but to take the issue to Parliament as the U.S. plan for taking military action failed to be prosecuted rapidly enough. Prevarication in Washington led to more of the same in London.
Third, this rupture in counter-proliferation cooperation was short-lived. Most notably, in April 2018, the Assad regime carried out another chemical weapons attack east of Damascus in Douma, and Prime Minister Theresa May made an executive decision to deploy British military forces alongside their U.S. and French counterparts. In hindsight, then, it is important not to exaggerate the Ghouta episode as signifying a deeper deterioration in the British-U.S. counter-proliferation partnership.
Wyn Bowen is head of the School of Security Studies, King's College London. He has written widely on WMD issues in the Middle East and North Africa region and was a U.N. weapons inspector in Iraq in 1997-98.
Matthew Moran is co-director of the Centre for Science and Security in the Department of War Studies, King's College London. His research focuses on the dynamics of proliferation behavior.
 See, for example, Richard K. Betts, "Two Faces of Intelligence Failure: September 11 and Iraq's Missing WMD," Political Science Quarterly, Winter 2007/2008, pp. 585-606.
 "Déclaration de M. François Hollande, Président de la République, sur les défis et priorités de la politique étrangère de la France, à Paris le 27 août 2012," XXème Conférence des Ambassadeurs, Paris, Aug. 28-29, 2012.
 Gen. Martin Dempsey, "Proposed Authorization to Use Military Force in Syria," Committee on Armed Services, House of Representatives, 113th Congress, 1st sess., Washington, D.C., Sept. 10, 2013, HASC no. 113-55, US GPO, 2014.
 Reuters, Aug. 27, 2013.
 David Cameron, For the Record(London: William Collins, 2019), p. 460.
 John Kerry, Every Day Is Extra(London/New York: Simon and Schuster, 2018), p. 531.
 James Strong, "Interpreting the Syria vote: parliament and British foreign policy," International Affairs, Sept. 2015, p. 1123.
 Samantha Power, The Education of an Idealist(London: William Collins, 2019), p. 373.
 Anthony Seldon and Peter Snowden, Cameron at 10: The Verdict (London: William Collins, 2015), p. 332.
 James Strong, "Why Parliament Now Decides on War: Tracing the Growth of the Parliamentary Prerogative through Syria, Libya and Iraq," British Journal of Politics and International Relations, Nov. 2015, p. 612.
 Seldon and Snowden, Cameron at 10, p. 345.