For all the talk of his need to exhibit global leadership in responding to allegations of chemical weapons use by the Syrian Government, it is sometimes easy to forget that President Obama is elected by a domestic constituency whose views need to be taken into account. As a second-term president, he would be less concerned about national sentiment, but he still has a domestic agenda to get through Congress so he needs to be aware of public concerns.

There isn't a great deal of support for military action against Syria. This is in many ways understandable. A decade of military action in the region that has cost the lives of thousands of troops and raised suspicion about the veracity of intelligence used to justify military action. The debacle of Iraq has meant that there is both a certain war-weariness and a disbelief in government guarantees about the necessity of action.

As recently as June this year, the US population was opposed to general US involvement in Syria, not supportive of arming the opposition and less than 50% of people supported military action if the use of chemical weapons was proven. More recent polls have again shown that military action against Syria, even in the event of proven chemical weapons use, lacks popular support.

If the decision to undertake military action wasn't already hard enough, the British Government has now ruled out its involvement in military strikes after a motion supporting such action was defeated in the Commons. Obama also faces a likely UNSC veto, yet he still needs to build at least a small international coalition, and select targets to minimise civilian casualties and avoid toppling the regime. He must do all this knowing there is no great domestic demand for him to do anything. Nobody ever said leadership was easy.