The West's response to the Syrian crisis is like "a monkey with a grenade," according to Russian Prime Minister Dmitry Rogozin. How far along the evolutionary chain U.S. Defense Secretary Chuck Hagel stands is, perhaps, a matter for debate, but by announcing that military assets have been readied to "comply with whatever option the president wishes to take" Hagel has confirmed that the military is ready to pull the pin if President Obama gives the word.
However, if it comes to military action it is unlikely that America will act alone. The French Prime Minister Francois Hollande has said that "France is ready to punish those who took the heinous decision to gas innocents," while British Prime Minister David Cameron has brought a healthy dose of bathos into international crisis management by tweeting the announcement that Parliament is to be recalled to debate British military intervention in Syria.
The contrast between Defense Secretary Hagel's rhetoric and David Cameron's decision to recall parliament is striking. In America, it appears, the president merely needs to say the word to send America's military into action, while the prime minister's approach suggests that Parliamentary approval is needed for British involvement. Advocates of strong checks on legislative authority should, however, pause before jumping to praise the British system: the difference between the two approaches is less about constitutional differences than political calculation.
In Britain, just as in America, the executive is able to use military force without parliamentary approval. The old "Royal Prerogative" has been inherited by the prime minister, meaning that he has considerable freedom of action in foreign affairs. Indeed, unlike in America, the prime minister does not need legislative approval to declare war, and there is no equivalent of the War Powers Resolution, which (while imperfectly implemented and constitutionally questionable) limits the duration that the American president can deploy forces abroad without Congressional approval.
The difference between Cameron and Obama's approaches is less to do with legal constraints, and more to do with political calculation. They are simply faced with different domestic circumstances, that require different responses. President Obama is a second term president, who will never seek election to public office again and whose authority is largely independent of Congress. On Obama's big domestic issues it seems unlikely that many within Congress will change the way they vote if he acts against Syria without consulting them.
However, if asked, Congress might vote against intervention, and any debate would give opponents of military action a platform to play on the fears of an already skeptical public by drawing comparisons with Iraq and questioning whether the economic climate is right for another costly foreign adventure.
The risks of going to Parliament are high for Cameron too, and he can expect a hard time from MPs looking to gain popularity with those who still feel betrayed by the way Parliament ignored public opposition to vote in favour of intervention in Iraq. However, he has little choice but to seek Parliamentary approval. As prime minister his position rests solely on Parliamentary support, a shaky foundation for a leader whose party won a minority of seats in the House of Commons at the last election. His Liberal Democrat partners have generally been skeptics regarding armed intervention, and there is a realistic possibility that their coalition government would collapse if he intervened against Syria without Parliamentary approval.
In addition, Cameron will no doubt have an eye on the May 2015 general election: bypassing Parliament would give Ed Miliband, the leader of the opposition Labour Party, an opportunity to curry favour with anti-war voters by attacking Cameron's "undemocratic" handling of the crisis, without actually having to risk coming out against an intervention designed to protect the victims of chemical warfare. By recalling Parliament Cameron has forced Miliband to release a statement which sounds rather like a watery version of the government's own position.
Any intervention in Syria, however limited, is bound to be a risky business for the leaders of the countries who will participate. If they are going about their preparations for intervention in different ways, it's not primarily about constitutional constraints or personalities, but about their need to reduce their exposure to those risks by minimising domestic political threats.