WASHINGTON (AP) — The Senate's top Democrat fiercely opposes expanded trade deals, but he signaled Tuesday he won't stand on the railroad tracks to block them.

Sen. Harry Reid of Nevada reminded reporters in the Capitol that he consistently has opposed President Barack Obama's bid for "fast track" authority on trade negotiations.

Under fast track — which, in a partisan twist, congressional Republicans generally support, and Democrats generally oppose — presidents can submit trade deals that Congress can endorse or kill, but not amend.

The House and Senate plan to vote on fast track legislation this year. Many labor unions and liberal groups hope to defeat it, saying expanded trade deals hurt U.S. jobs.

They'd love to see Congress' Democratic leaders — Reid in the Senate, and Minority Leader Nancy Pelosi in the House — leading the opposition. But neither has flatly rejected the fast track legislation, and Reid sounded a bit resigned Tuesday.

"I'm leaving this to my colleagues to parse out what's good and bad in the bill," he said.

One Senate Democrat announced his opposition on Tuesday.

"It's being negotiated behind closed doors, yet I'm being asked to give my approval before Americans can know the details," Sen. Tom Udall of New Mexico said in a statement. "I cannot support broad presidential authority to fast-track such a wide-ranging deal, which would limit the Senate's ability to review trade agreements and represent our constituents' interests."

Senate Majority Leader Mitch McConnell, R-Ky., said he hopes to take up the fast track legislation soon. If it passes, Obama is likely to ask Congress to approve a long-negotiated trade agreement with 11 other Pacific-rim nations. Other free-trade deals could follow.

Reid said the Senate should handle several non-trade issues before taking up fast track. The White House gently rejected that idea.

"Surely we should be able to expect the United States Senate to do more than one thing over the course of this month," said presidential spokesman Josh Earnest.

Reid said he wants three other trade-related bills rolled into the fast-track legislation, which possibly could complicate or slow matters. Those bills involve "trade adjustment assistance," or federal help for displaced workers; a customs enforcement measure; and a three-year extension of the African Growth and Opportunity Act.

McConnell, who's not known for cracking one-liners, told reporters he's having "an almost out-of-body experience" by working so closely with Obama on trade legislation.