WASHINGTON (AP) — Led by union-backed Democrats, the House delivered a stinging blow to President Barack Obama on Friday and left his ambitious global trade agenda in serious doubt.

Republican leaders, who generally support Obama's trade objectives, signaled they might try to revive the package as early as next week. But that could require the shifting of at least 90 votes within either or both parties, a heavy lift.

Friday's setback was deep and personal for Obama, who made a surprise, last-minute trip to the Capitol to ask House Democrats to back him.

Not only did they reject him by the dozens, they were led by party leader Nancy Pelosi of California, who has often expressed deep admiration for the president. She joined in a tactic that even some Democrats called devious and cynical: voting against a favorite job-retraining program in order to imperil the trade package's main component: "fast track" negotiating authority for Obama.

Hours earlier, Obama had specifically asked Democrats not to do that. But in a crowded House chamber, Pelosi urged her colleagues to ignore him.

"Slow down the fast track to get a better deal for the America people," she said, drawing praise from labor unions, liberals and others who say free-trade deals send U.S. jobs abroad.

Other presidents have had fast track authority, which lets them propose trade agreements that Congress can ratify or reject but not amend. The administration currently is trying to conclude negotiations with 11 Pacific-rim countries including Japan and Canada. Other trade agreements could follow.

One possible route for pro-trade forces in Congress 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 spokesman Josh Earnest said Friday's vote showed congressional support for fast track, and "our work is not done yet." As for Democrats rejecting the retraining program, he said, the administration will contend "they have registered their objections to (fast track) and it didn't work." Earnest said the administration will urge Democrats to "support a policy that they have strongly supported in the past."

Friday's crucial vote came when 144 House Democrats joined 158 Republicans to reject extension of Trade Adjustment Assistance, or TAA. The program, which helps workers who lose their jobs to international trade, has long been a priority for Democrats and unions.

But the Senate had tied it to the broader fast track negotiating authority for the president, which House Democrats overwhelmingly oppose. Egged on by the AFL-CIO, Pelosi and others, the vast majority of House Democrats voted against the retraining program as a means to scuttle the entire package.

Moments later, the House did vote, 219-211, to endorse the fast track portion of the package, but that could go nowhere without the first part. Only 28 Democrats joined 191 Republicans in voting for it. Voting no were 54 Republicans and 157 Democrats.

Pro-trade forces now must either reverse the retraining program's fate or send a revised fast track bill back to the Senate, and hope for the best. GOP aides said more Republicans might possibly hold their noses and vote for the training in order to save fast track, a mirror-image of the Democrats' counter-intuitive strategy.

House GOP leaders suggested it's up to Democrats to revive the trade package. "The president has some work yet to do with his party to complete this process," said Rep. Paul Ryan, R-Wis., a leading author of the trade legislation. "This isn't over yet."

AFL-CIO President Richard Trumka hailed Pelosi, saying, "She stood up against corporate interests and, as always, put first the people who are too often left out of trade agreement discussions."

The trade issue is certain to reverberate in next year's presidential election. Most Republican contenders favor the trade bill. Among Democrats, Hillary Rodham Clinton is uncommitted, despite rivals' calls to take a position.

Obama drew applause when he walked into the morning meeting with Democrats, but sharp words after he left.

Rep. Peter DeFazio, D-Ore., was especially withering.

"He's ignored Congress and disrespected Congress for years," he told reporters, "and then comes to the caucus and lectures us for 40 minutes about his values and whether or not we're being honest by using legislative tactics to try and stop something which we believe is a horrible mistake for the United States of America, and questions our integrity. It wasn't the greatest strategy."

Obama says U.S. products must reach more markets. He says unions and others should stop harping on perceived harm from the 1995 North America Free Trade Agreement, of NAFTA, which many critics accuse of shipping American jobs overseas.

Globalization, technological advances and other changes in the past 20 years, Obama says, make expanded trade essential.