Image copyright Reuters Image caption President Obama's move has left commentators questioning his leadership

President Obama has taken the biggest gamble of his presidency.

His decision to put off an attack on Syria and seek authorisation from Congress apparently stunned some of his closest advisers.

Secretary of State John Kerry has defended the president's abrupt change of approach, telling NBC: "He didn't think it was worthwhile acting and having the Syrians and a whole bunch of other folks looking at the United States arguing about whether or not it was legitimate, or should he have done it, or should he have moved faster."

But that is precisely what will happen for at least the next 10 days. There's lots of criticism already and a lot of rehashing of how he got to this position.

Only on Friday, the Secretary of State went out on a limb stressing what was at stake for the world and America's reputation. It is hard to imagine that he's best pleased that Assad's punishment has been put on hold.

If Congress votes "No", his words will come back to haunt him and Obama.

That could happen: victory is by no means assured, particularly in the Republican-controlled House of Representatives. Perhaps the Senate isn't safe either - this will be a free vote and there'll be no formal attempt by party leaders to persuade their colleagues.

After receiving a lengthy classified intelligence briefing on Capitol Hill, several senators and congressmen seemed unconvinced.

The draft resolution from the White House calls for authorisation for action to "deter, disrupt, prevent and degrade" Syria's ability to use chemical weapons: two senators - one Republican, one Democrat - called that too open-ended.

Republican Senator John McCain, who has been leading the demand for military intervention in Syria, said that there was "no strategy, no plan" - and both were needed before he'd back the motion.

If Congress doesn't back him, it will be disastrous for the president.

His decision to call for a vote will look foolish and he would be left with an appalling choice.

Ignore the vote and enrage Congress and many Americans. Or don't strike and live with John Kerry's words that America will be weakened, petty dictators emboldened and history's judgement harsh on America's leaders.

So everything hangs on Obama winning the vote. But even if he does, the delay gives Assad more time to prepare for the blow.

The decision has left many commentators questioning his leadership and asking how Obama managed to box himself in.

But to have taken action without the UN, without the UK, without Congress and without the American people's support would have been very uncomfortable for a man who came to office vowing to end America's foreign wars.