President Obama: The president put the clout of the White House on the line when he turned to Congress for authorization to attack Syria. But lawmakers turned against his plan, in part because constituents were calling their offices night and day to urge opposition. Having drawn a "red line" over the use of chemical weapons in the ongoing Syrian civil war, the president risked a situation in which he would need to either ignore the will of Congress or allow the Syrian regime’s use of chemical weapons pass with impunity.

The opening of a possible diplomatic solution allows the president to walk his proposal back, or even, as some Democrats have argued, to take credit for pressuring Russia and Syria into making diplomatic concessions.

“The only reason that Russia is moving to the U.N. … is because of the pressure. It’s because of the threat of a strike by the president, because of the possibility that Congress would authorize” the use of military force, Sen. Carl Levin, D-Mich., said.

Republican House Leaders: Speaker John Boehner, R-Ohio, called on his Republican colleagues to be “supportive” of the Democratic president — though many opposed Obama — when a vote on the war resolution appeared imminent. “There's one person that speaks for the United States of America when it comes to foreign policy, and that's the president of the United States," Boehner said.

Still, many of Boehner's fellow House Republicans had no interest in following his lead in supporting a military strike. Despite Boehner and Majority Leader Eric Cantor’s support for a military strike, a House vote would have almost certainly yielded a lot of Republican "no" votes. The opportunity for a diplomatic solution helped Boehner escape an embarrassing outcome.

Bashar Assad: The possibility of a diplomatic solution involving the U.N. may allow Syrian President Bashar Assad to trade his chemical weapons stockpile for a pledge by the United States and its allies not to launch military strikes against him. And while military strikes may have weakened Assad's grip on power, confiscating Syria’s chemical weapons is unlikely to give the country’s armed opposition any strategic gains.

House Minority Leader Nancy Pelosi, Senate Majority Leader Harry Reid: The top two Democrats in Congress had the onerous task of convincing fellow Democrats to support Obama’s strategy. The difficulty: Many of their colleagues were elected by a public deeply weary of war in a party with a recent history of expressing skepticism over any military intervention. As with Boehner and Cantor, the "no" votes were adding up among Democrats in both the House and Senate. Hitting the pause button on congressional authorization for the use of military force allows them to regroup – or perhaps even avoid – the difficult job of cobbling together enough votes to sustain the president's request for authorization.

-- Congressional Correspondent Tim Mak