The decision of the UK parliament to refuse approval for a military strike on Syria has helped influence President Barack Obama to put his own plans before Congress, analysts say.
Though Mr Obama has stated that he still supports military action before the UN inspectorate has reported, and irrespective of a UN Security Council vote, his aggressive stance has been moderated by the decision to seek congressional authorisation for strikes.
That, in turn, state department officials conceded, had been influenced by the UK parliamentary debate and by the withholding of majority support for immediate (some critics would say pre-emptive) response as a result.
Mr Obama's calculation is that, unlike Mr Cameron, he will win the backing of lawmakers that he seeks. But it is far from a done deal, with US public opinion sceptical or hostile, and made more uncertain by the refusal of Britain and Germany to join a strike coalition. French support is still considered insufficient or flaky in many quarters.
The earliest a congressional vote can happen is 9 September 2013. The US President believes that this will allow time for building support for armed action, while those who oppose military escalation hope that the flames of conflict can be dampened.
Yesterday (31 August) former Liberal Democrat leader Paddy Ashdown, an enthusiastic proponent of armed action, argued that a further vote at Westminster might be possible after the Congress decision.
At present there is little appetite for this, but resolute pro-interventionists are thought to be biding their time with that thought in mind.
Another scenario is that Mr Obama will in fact launch an unexpected early strike on Syria, on the pretext of 'changing realities on the ground'. This would carry enormous risks and consequences, however.
Politically, the US Commander-in-Chief is wanting to be seen as a hawk to thwart the more extreme proposals of John McCain and others, some of whom who would favour a ground war and regime change, while also appearing flexible and restrained to the large swathe of the US public tired of war and military 'mission creep'.
David Cameron has said he still supports the idea of a military strike, even though he respects the House of Commons vote against.
The two men appear to be using the situation together to build or rebuild respect and support – though there is little doubt that the Pentagon's overwhelming intentions are to pursue what it sees as its own interests, regardless of "the foreign policies of other nations", as unexpectedly belligerent Secretary of State John Kerry has put it.
The political calculations and positioning will certianly continue in the coming days, as other countries decide where they stand.
The Stop the War Coalition said yesterday that the Westminster vote "represented the victory of mass anti-war opinion over the interests of the UK elite that has been enthusiastically participating in US-led wars over the last decade and more."
It continued: "There can be no doubt that the hundreds of demonstrations, protests, rallies and pickets of the last twelve years have been central to making it impossible for Cameron to join in another catastrophic attack.
"Obama and the remaining US allies are still committed to an attack on Syria. Britain was the key US ally. Forcing Cameron out of the war is a big blow to these war plans."
* Congress involvement creates global uncertainty over Syria action: http://www.ekklesia.co.uk/node/18967
* Commons Syria vote: a significant moment, but what next?: http://www.ekklesia.co.uk/node/18948
* More on Syria from Ekklesia: http://www.ekklesia.co.uk/syria