Have the first congressional votes in a decade on authorizing military force been postponed indefinitely, or effectively canceled altogether?

Members returned to work Wednesday scratching their heads over that question, which President Barack Obama left unanswered during his speech to the nation Tuesday night. Lawmakers got no guidance from the White House, which declined to offer any sort of deadline for its sudden switch to pursuing a diplomatic resolution to the crisis in Syria.

A bit more definition is possible when Secretary of State John Kerry meets with Russian Foreign Minister Sergey Lavrov in Geneva on Thursday to negotiate details of a seemingly long-shot plan for teams of international monitors to collect and destroy all of President Bashar al-Assad’s chemical weapons.

There’s also a chance for some timeline to emerge at the United Nations, where delegates from the United States, France and Great Britain are working on a Security Council resolution requiring the government in Damascus to turn over its stockpile or face globally sanctioned military reprisal.

The deliberative metabolism of diplomacy and the complexities of the plan sprung only in the past few days suggest it will be near the end of the month before it’s plausible to decide whether the Russian and U.N. approaches can be sustained.

It will also probably take a couple of weeks to discern if Syria, which has signaled cooperation with Russia’s disarmament call, is only doing so as a stalling tactic — designed to play for extra time, during which congressional and public support for a punitive strike might shrink even more than it already has.

Coincidentally or not, the president’s call for a timeout in his drive for the Hill’s backing came after it was abundantly clear he wasn’t even close to having the votes he needed, and that his chances were slipping by the hour.

By the time he went before the prime-time TV cameras, tallies of lawmakers’ stated positions showed Obama had at most two dozen “yes” votes locked down in the Senate and at least three dozen senators against giving him the authority. The latter was very close to the 41 needed to stop the use-of-force resolution with a filibuster.

The unofficial whip counts in the House were even more problematic: Less than 10 percent of members were in favor of a military strike, at least 40 percent committed in their opposition and at least another 10 percent leaning toward “no.”

The decision to grab at diplomatic options, even knowing they might dissolve into mirages soon enough, buys not only Obama but also a balky Congress an uncertain amount of leeway to paper over their differences. All the players are war-weary. They’re just figuring out how to exorcise their exhaustion in different ways.

A good bet is Obama won’t take his hand off the congressional pause button unless he’s confident he’s turned legislative momentum in his favor. Having extracted himself from an almost certain defeat that would have weakened his standing abroad and on the Hill, he has absolutely nothing to gain from subjecting himself to that predicament again.

There’s a chance the president will eventually declare that the need for a congressional vote has become moot, and most members will tacitly defer to him. That could happen if:

• Almost the whole world lines up behind U.N. language countenancing airstrikes if Syria doesn’t make good on its promises and there’s a face-saving consensus in Congress that such a resolution gives Obama the only official stamp of approval he needs to send in the Tomahawks if necessary.
• Syria bends over backwards in cooperating, refuting the skeptics who say it’s nearly impossible under ideal circumstances — let alone during a civil war — to rapidly collect unconventional weapons from dozens of widespread secret locations.

More likely, there will be a new drive to rally Congress behind a conditional use-of-force resolution once Syria’s cooperation looks to be neither genuine or fast enough for the comfort of the administration or congressional hawks. A fine time for that scenario to start moving to the fore is the week after next, when the House is still awkwardly on course to be away for an end-of-the-fiscal-year “district work period.”

If the GOP majority leadership sticks by that schedule, it would generate just the sort of news vacuum that could be filled by Republican Sens. John McCain and Lindsey Graham. They remain the most strongly in favor of punishing Syria with military might and the most keenly interested in asserting either the congressional prerogative or the political imperative for granting permission for such shows of force.

McCain said Wednesday that he won’t wait long before deciding if Syria is deploying a “rope-a-dope” delaying tactic.

Obama “sure has created one awkward situation for himself,” says Julian E. Zelizer, a presidential historian at Princeton University. “If he returns to the Hill to ask for any kind of authorization, he’ll have to admit his diplomacy didn’t work, which will put him in an even weaker position than he is now and make it even harder for him to get what he wants.”