WASHINGTON - At first it seemed like just another of John Kerry's musings - Syria could stop threatened US military strikes by placing its chemical weapons stockpile under international control.
But within hours, as the US top diplomat was still in the air flying back to Washington from London, what appeared to be an off-the-cuff remark caught fire, with Russia embracing it and the Syrian regime also seemingly coming on board.
Late Monday, Obama appeared to give it his blessing, saying that what was now being seen as a surprise Russian initiative could prove to be a "significant breakthrough" in changing the course of the brutal Syrian war and the thinking of the Syrian regime.
"I think what we're seeing is that a credible threat of a military strike from the United States, supported potentially by a number of other countries around the world, has given them pause and makes them consider whether or not they would make this move," Obama told NBC.
"And if they do, then this could potentially be a significant breakthrough. But we have to be sceptical because this is not how we've seen them operate over the last couple of years," the commander-in-chief said a day before he is due to address the nation.
He told Fox television that Kerry would be in touch with Moscow to see if there was an "enforceable mechanism to deal with these chemical weapons in Syria."
Political tensions are high in Washington with Congress beginning to debate a resolution calling for approval of US military strikes against the Syrian regime after a suspected August 21 gas attack on a Damascus suburb.
So, in a war-weary world, perhaps it should be of little surprise that Kerry's idea gained swift traction.