WASHINGTON - The White House and Republican leaders in Congress face long odds in trying to revive trade legislation after a telling defeat engineered by President Barack Obama's fellow Democrats.

Obama's ambitious trade agenda is in serious doubt, as is his quest for a capstone second-term achievement.

Without the power to negotiate trade deals that Congress can approve or reject, but not amend, Obama has little chance of securing the Pacific Rim pact that his administration has worked toward for years.

Friday's rebuff highlighted the strained relations between Obama and congressional Democrats, who voted down a worker assistance program crucial to the negotiating authority measure just hours after the president implored them not to.

Obama and House Speaker John Boehner, R-Ohio, had worked in rare tandem on this issue, yet their inability to deliver raises the question of whether much else will get done with Republicans running Congress and Obama in the White House for the next 18 months.

"This isn't over yet," Rep. Paul Ryan, R-Wis., a main supporter of the trade legislation. "I'm hopeful that the Democrats understand the consequences and get together with the president and finish this as soon as possible."

House GOP leaders took steps that would allow another vote on the worker retraining program in coming days, but that would require at least 90 votes to shift.

Republicans sounded pessimistic that they could add many more votes for a program that most on their side deride as wasteful and unnecessary.

House Democratic leader Nancy Pelosi of California and her labor-backed allies are determined to oppose the Trade Adjustment Assistance program as a way to collapse the entire package. So it seems unlikely that enough Democratic votes would emerge to save the program, even though the party has promoted it for years.

"Some of my Democratic colleagues are in danger of self-immolation" on the workers' program and "I think that's sad," said Rep. Kurt Schrader, D-Ore., one of the few Democrats who backed Obama on Friday's votes.

Another possible route is to send revised legislation back to the Senate. But senators approved the larger package only narrowly last month after intense battles, and the White House desperately wants to avoid giving opponents there another chance to strangle the legislation.

White House press secretary Josh Earnest dismissed Friday's outcome as an "entanglement" and "procedural snafu."

But it was more than a "snafu" that caused Pelosi and the majority of House Democrats to revolt against their president.

The White House, congressional Republicans and business groups argued that the special negotiating power is a necessary tool for trade deals opening up crucial markets to American goods.

Union-backed House Democrats never bought the argument. They felt burned by promises from past administrations about trade deals they blame for job and manufacturing losses in their districts.

Trade bills have always had a tough road in Congress. After election losses in recent years the House Democratic caucus is smaller and more liberal, attuned to economic issues in the wake of the financial sector meltdown and recession.