The Republican-led Senate ignored a White House veto threat Wednesday and voted to block President Bush from handing some Homeland Security Department (search) jobs to private companies.

A victory for Democrats and labor unions representing federal workers, the 49-47 vote was an embarrassing setback for Republicans and a bow to election-year pressures. And it further snarled efforts by GOP leaders to adjourn Congress for the year in October, before the Nov. 2 elections.

The language was added to a popular $32 billion bill financing the Homeland Security Department next year. The White House budget office warned of the veto in a written statement to lawmakers.

The amendment would "preclude public-private competition and turn back ... efforts to significantly improve customer service for immigrants," the statement said.

Sen. Patrick Leahy (search), D-Vt., a chief sponsor of the provision, said it was aimed at preventing Bush from replacing 1,100 immigration officers who screen applications and perform criminal background checks.

"They try to weed out terrorists," Leahy said.

Republicans said the workers in question perform administrative duties.

But the GOP-run House has approved a similar prohibition on outsourcing, amid a Bush effort to replace some federal workers with private employees across government.

Five Republicans from states with a significant labor presence joined Democrats in voting for Leahy's amendment: Sens. Olympia Snowe (search) and Susan Collins of Maine, Lincoln Chafee of Rhode Island, Christopher Bond of Missouri and Arlen Specter (search) of Pennsylvania. Bond and Specter are seeking re-election this year.

The vote came a day after lawmakers returned from a six-week summer break that included both parties' national conventions. House leaders were talking about recessing for the year Oct. 1, but Senate leaders were aiming for a week later, and no one was ruling out an Oct. 15 departure.

Others said a session after the elections looked increasingly likely. A lame duck session could be needed to finish reshaping the government's intelligence apparatus and Congress' oversight of it; to provide emergency aid to hurricane-battered Florida and other areas; and to finance almost every federal program in the budget year that starts Oct. 1.

Even so, the approaching presidential and congressional elections were pressuring lawmakers to finish some bills. Among them was the Senate's Homeland Security Department bill, though Wednesday's vote on jobs complicated its fate.

Both parties had agreed there would be no attempts to delay that bill's completion.

Democrats said they were motivated partly by their experience in 2002, when many of them opposed a bill creating that department because of a dispute over labor protections. Republicans accused them of not caring enough about protecting the country, and one Democrat — Sen. Max Cleland of Georgia — was defeated.

"Everybody is very much conscious of what happened in 2002," said Sen. Ron Wyden, D-Ore.

Of the 13 annual spending bills for the coming budget year, only one — financing the Defense Department — has become law. The Homeland Security bill would be only the second the Senate has finished, while the House was debating its eleventh spending measure.

On Wednesday, House debated a $142.5 billion bill financing next year's health, education and labor programs.

Rep. Bernie Sanders, I-Vt., citing a jump in home heating oil costs, won a $22 million increase in funding for the $2.2 billion Low Income Home Energy Assistance Program and the $227 million Weatherization Assistance Program.

Debate on the bill ended before dinner Wednesday as Republican leaders hunted for votes to derail a Democratic amendment challenging major changes to the nation's overtime pay rules that the Bush administration implemented last month. The vote is expected Thursday.