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 top US 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 coming on board - even though the regime has never admitted to possessing chemical weapons.
In the slow-moving world of international diplomacy, where every remark is carefully calibrated and deliberated, it's rare to see ideas spread like wildfire.
Asked early on Monday in London if there was anything Syrian President Bashar al-Assad could do to avert a US military strike, Kerry replied: "Sure."
"He could turn over every single bit of his chemical weapons to the international community in the next week. Turn it over, all of it, without delay, and allow a full and total accounting for that," Kerry said. He quickly seemed to shoot down his own idea, adding: "But he isn't about to do it, and it can't be done, obviously."
Seemingly caught off guard, State Department spokeswoman Jen Psaki issued an e-mail saying Kerry "was making a rhetorical argument about the impossibility and unlikelihood of Assad turning over chemical weapons he has denied he used".
Reporters travelling back to Washington aboard Kerry's plane were assured that there was "no serious proposal" to address Syria's chemical weapons stock on the table.
But while Kerry was still in mid-flight, Russian Foreign Minister Sergei Lavrov took up the suggestion, calling on Damascus to "place the chemical weapons under international control and then have them destroyed".
Such a plan would help "avoid military strikes", Lavrov insisted, apparently after he had talked for 14 minutes with Kerry two hours after take-off from London.