In consulting Congress on Syria, Mr Obama has changed the US constitutional balance

With the US public “war weary”, the dynamics of Capitol Hill unfavourable, and the British Government’s defeat so fresh, success is by no means assured

Following last week’s surprise parliamentary defeat over Syria, there has been much talk of the long shadow of Iraq, of poor government whipping and, in some quarters, of the perfidious politicking of the Opposition. But with the majority of the public opposed to military action, the result that so humiliated David Cameron was simply democracy at work. And as this weekend’s events on the other side of the Atlantic make plain, the consequences are only just beginning to be felt.

Even as the US spent the past week preparing for retributive air strikes, the equivocation of the President was evident. It was left to Secretary of State John Kerry to fulminate against the “moral obscenity” of chemical weapons, while Barack Obama talked in measured terms of a “limited, tailored” operation and a “shot across the bow”. The parliamentary wing-clipping of Mr Obama’s supposedly reliable British partner might have been met with White House declarations that the US would not be deterred. But the bravado proved unsustainable and, in a hastily convened Rose Garden appearance on Saturday evening, the President confirmed that although he had made up his mind to take military action, the decision would be ratified by Congress first.

In the immediate term, the move is significant enough. The President was keen to stress that the proposed action – “limited in duration and scope” but still enough to “hold the Assad regime accountable” – is not time dependent. Perhaps, given evidence that the Syrian government is already shifting its matériel, the operational advantages of an early strike have already been lost. But with pro-Assad Russia still demanding a (veto-able) UN resolution, and the G20 meeting in St Petersburg this week, the legal and political climate will not get any easier the more time passes.

Meanwhile, with Congress not due to reconvene until 9 September, Mr Obama has a week to persuade reluctant US lawmakers to support intervention. The White House will lobby hard. But with the US public “war weary”, the dynamics of Capitol Hill unfavourable and the British Government’s defeat so fresh, success is by no means assured.

Regardless of the outcome, the President’s decision to consult Congress has far-reaching implications. As Commander-in-Chief, Mr Obama’s powers to commit the US to war are open to interpretation. That he felt the need to seek explicit legitimacy from legislators speaks volumes about his concern at the legal basis for action in Syria, and also about his sense of isolation, faced with an ambivalent public and with a crucial ally lost. Yet in choosing to put the matter to a vote, Mr Obama has changed the constitutional balance of the US; for better or for worse, future presidents will find it difficult not to follow his example.

Nor do the repercussions end there. Thanks to his US counterpart, the pro-intervention French President is also now facing pressure to hold a parliamentary vote on Syria. The ripples from Mr Cameron’s humbling defeat are spreading wide, indeed.