WASHINGTON (AP) — Union-backed Democrats launched a last-ditch effort Thursday to scuttle President Barack Obama's trade agenda by sacrificing a favored program of their own that retrains workers displaced by international trade.

The retraining program is linked to the Democrats' real target: legislation to help Obama advance multi-nation trade agreements. In hopes of bringing down the whole package, which they say imperils jobs at home, numerous House Democrats said they would vote Friday against the retraining measure.

The trade authority is a top priority for the president, who hopes to complete a major deal with 11 Pacific Area nations. But the bill has drawn fierce opposition from Democrats, many of them supported by unions who argue that expanded global trade will cost jobs at home.

House Republicans were in the odd position of supporting Obama's bid for "fast-track" trade-negotiating authority, while the White House struggled to come up with enough Democratic votes to win passage.

In a closed meeting in the Capitol, top White House officials implored Democrats not to deny Obama the trade authority. Such a vote, they said, would block needed trade expansion for the nation and sink a major priority of the Democratic president.

The sometimes emotional exchanges illustrated the high stakes and intense feelings surrounding Obama's bid for "fast track" trade-negotiating authority. Such authority, which previous presidents have enjoyed, would let Obama present Congress with proposed trade agreements that it could ratify or reject but not change.

Obama hopes to advance the 12-nation Trans-Pacific Partnership and other trade proposals that have been negotiated for years.

Unions vehemently oppose such deals, saying they ship U.S. jobs abroad.

The trade issue's divisiveness was evident when the House voted narrowly, 217-212, on a procedure to advance the package to Friday's expected showdown.

AFL-CIO President Richard Trumka urged House Democrats to do something once unthinkable — reject the retraining program, known as Trade Adjustment Authority, or TAA — as the best means to kill fast track. Those attending the meeting said Trumka told Democrat he would pray for those who oppose the unions' position.

Some senior Democrats are with Trumka, suggesting Friday's votes could be close and dramatic.

"The TAA is the handmaiden to facilitate the whole deal," said Rep. Peter DeFazio. "We have the potential to stop this whole train and revisit the most egregious provisions" of fast track. "It's counterintuitive for Democrats to be voting against it, but President Trumka came and said vote against it."

The strategy could scuttle the whole package, because many Republicans have long records of opposing the jobs retraining program, which they consider wasteful.