President Obama addresses nation on Syria

FOX NEWS -- President Obama, in an address to the nation on Syria, said Tuesday he has asked Congress to "postpone a vote" on military action in Syria in order to make room for diplomatic negotiations that could avert a strike.

The president said the recently emerging talks have the "potential to remove the threat of chemical weapons without the use of force."

Related: The full transcript from President Obama's address on Syria.

The president, though, continued to call for the threat of U.S. military action as a fallback in case the diplomatic course does not work. He said that while he had resisted calls for military action in the country's civil war, the situation "profoundly changed" after the Assad regime "gassed to death" hundreds of people last month.

The president addressed the nation a little more than a week after declaring he would seek congressional support for a military strike on Syria, in response to a chemical weapons attack on Aug. 21.

But the environment changed rapidly over the past two days, forcing Obama to recalibrate his approach and walk back his "red line" threats, while still leaving open the door to military action.

The game-changer came after Secretary of State John Kerry at first casually floated the idea of Syria turning over its chemical weapons to avert a strike. The Russians then swiftly adopted the idea as a formal proposal, which Syrian government officials now say they will accept, forcing the Obama administration to give it a chance. Kerry will travel to Geneva on Thursday to speak with his Russian counterpart.

Senior Obama administration officials on Tuesday claimed that the White House has been working on such a chemical weapons hand-over plan with the Russians for up to a year. But they acknowledged that Kerry got ahead of the process when he made the off-handed remark on Monday morning.

Obama is now in a tricky spot, balancing between the threat of military action and a stated desire to pursue the diplomatic track. He and his top officials are publicly wary that the Assad regime would fully comply with a plan to turn over its chemical weapons.

At the same time, Obama continues to face an uphill climb in getting Congress to approve the use of force.

And with the possibility of a diplomatic solution on the table, some congressional leaders - House Democratic Leader Nancy Pelosi among them -- were even less inclined to entertain a vote on military action.

"It is not necessary for Congress to give the president this authority," Pelosi said. "We are grateful that he has asked for it but if he sees an opportunity we don't want the Russians to think that his leverage is diminished because of a vote (that) may or may not succeed within the Congress."

Russia's Vladimir Putin sought to use the sudden change in dynamic to his advantage, and the advantage of his ally Bashar Assad. He demanded Tuesday that the U.S. abandon discussions on military action - a statement Sen. John McCain, R-Ariz., who supports military action, called "unacceptable."