You can't accuse America of a rush to judgement. It has taken US intelligence months to conclude, publicly at least, that the Syrian regime has indeed used chemical weapons against its own people and crucially crossed President Obama's red line.
So why has it taken so long?
The answer is that the American administration is deeply and sincerely divided about how to react.
On the one hand, the State Department and the new National Security Advisor, Susan Rice, urge a more aggressive intervention.
On the other, a President elected to end wars in Afghanistan and Iraq, is supremely reluctant to get embroiled in another.
That also explains what you might charitably call the creative ambiguity of the White House briefing late last night.
The military aid America says it will supply opposition fighters falls short of an explicit promise to arm the rebels.
The best guess is that the help will amount to rifles and ammunition, but not all the heavy calibre equipment the Free Syrian Army craves.
In trying to even up the odds on the battlefield, where Assad and his allies from Hezbollah are winning, the US has to be careful not to trigger a regional arms race.
American rifles would easily be trumped by Russian anti-aircraft missiles, already promised to Assad, but not yet delivered.