After John Kerry told Syria it had one week to surrender its chemical weapons or face US airstrikes, Russia stepped in by proposing Syria transfer its chemical weapons to international control. Syria agreed, and the French are working on a UN resolution to formalize the arrangement. It looks like the diplomatic breakthrough could avoid a war, so Obama supporters have been quick to claim that that was the president's plan all along. David Axelrod asked over Twitter yesterday whether anyone though the breakthrough would've been possible absent the threat of military force.
It's a convenient fiction that makes the Nobel Peace Prize recipient's recent campaign for war seem like just another diplomatic tactic. While it's certainly possible Syria and Russia would be less motivated to find a diplomatic solution to a problem that didn't involve US military intervention, a diplomatic solution never appeared to be what the Obama Administration had in mind as an end game. The statement John Kerry made that got the diplomatic ball rolling, after all, was uttered sarcastically. Neither Kerry nor Obama expected Syria to respond to it in good faith—hardly the expectations of people making a good faith attempt at diplomacy.
Additionally, if the threat of military force were actually intended to secure a diplomatic breakthrough, then the president would not have went to Congress for a vote on Syria. After all, Obama has consistently denied he needs Congressional authorization to act. Were the purpose of the threat of military force jumpstarting diplomacy, opening that threat of force to a Congressional vote far from guaranteed to be a success would be counterproductive. Threats work best when they're not subject to question marks. And last night, Obama further weakened the argument that diplomacy was his plan all along by asking Congress to delay the vote. If the possibility of using military force was meant to pressure Syria and its allies to act responsibly, Congressional approval would only strengthen the power of that tactic.
No, far more likely is that the president called for a vote in Congress after seeing reticence among his allies and the American people for war, and hoping a vote in Congress, if in the affirmative, would help him shift blame if things go wrong, and that a vote in the negative could be used as an excuse to blame inaction on others. After all, it wasn't Constitutional concerns that drove the president to Congress, or he wouldn't have claimed to have the authority to act on his own.