A toxic brew of election-year politics, poor relations between President Bush and Democratic leaders and passionate union opposition threatens to scuttle the Colombia Free Trade Agreement, one of the few items left on Bush’s to-do list.

Apart from the economic stimulus package, trade pacts are one of the few initiatives where Bush has sought to accommodate Democrats, as opposed to the hard-nosed approach that smashed Democratic plans to withdraw troops from Iraq, expand children’s health insurance and boost domestic spending. The administration and industry backers note that most of Colombia’s products already have free access to American markets, but U.S. goods still face stiff tariffs entering Colombia.

Unlike the free-trade deal with Peru last year, which easily passed with significant Democratic support after Bush agreed to insert new labor and environmental standards, Colombia has fervent opposition from unions, including the AFL-CIO, primarily because of the continuing murders of union members.

The deal also suffers from unfortunate timing. Supporters had hoped that a window would open this spring for a bipartisan deal after the presidential primaries were over but before the fall campaign began in earnest. The primary fight between Sens. Barack Obama (D-Ill.) and Hillary Rodham Clinton (D-N.Y.) has hurt prospects for a deal, advocates on both sides of the debate say. Obama and Clinton oppose the Colombia agreement and trade pacts have become a lightning rod issue in battleground states such as Ohio and Pennsylvania.

The administration repeatedly has signaled that it intends to send the agreement to Congress in the next few weeks to guarantee a floor vote while Bush remains in office under fast-track rules, but Speaker Nancy Pelosi (D-Calif.) warned them not to do so without first consulting Democratic leaders. Pelosi also said before the March recess that a robust Trade Adjustment Assistance bill for displaced workers would be a prerequisite.

There is little doubt that Pelosi could scuttle the agreement on the floor if she chose to wage a campaign to kill it, and so the Bush team has met with Democratic leaders for more than a year to compromise. Bush officials now complain that Pelosi has shifted her demands and has yet to lay out exactly what the administration would need to do to secure her support.

“The goal posts have been moved to an undisclosed location,” an administration official quipped.

The official said the administration has bent over backward to work with Democrats, noting that the administration could have sent the Colombia deal to Congress and forced a vote at any time.

“The Colombia Free Trade Agreement was reached Nov. 22, 2006,” the official said. “We’ve held it for 491 days because we have been working with them. That has gone above and beyond any normal process.”

Unions are growing increasingly confident that they will be able to kill the deal on the House floor. They dismiss the much- ballyhooed labor standards, calling them useless unless Colombia enforces and protects labor rights.

“What good is that labor language when we know from day one that the government is going to be in violation?” asked Jeff Vogt, a trade policy specialist at the AFL-CIO. “No labor chapter will be sufficient to address the situation in Colombia when union members are killed for exercising their basic labor rights.”

The administration and the Colombian government contend that there have been improvements in limiting violence against unions, but critics are skeptical.

“Just this year alone we’ve seen a trade unionist murdered a week,” Vogt said.

Support from businesses also is intense, and many Democrats, including Ways and Means Chairman Charlie Rangel (N.Y.), want to vote for a free-trade deal. Many Democrats will face uncomfortable votes if a deal comes to the floor that could help out exporters in their districts but anger unions. They might need political cover if they vote for a deal.

The administration also has sought to make the issue into one of national security, given the aid the United States sends to Colombia to prosecute the drug war and its role as an ally and counter to anti-American President Hugo Chávez in Venezuela, but that issue doesn’t seem to have much traction with Democrats.

“For the longest time, the administration dismissed out of hand the concerns about violence and focused on the national security-Chávez argument,” said a House Democratic aide. “It was Chávez, Chávez, Chávez.”

Democrats who want to be supportive of a deal say the administration also needs to learn how to lead with carrots, not sticks.

“He should start off with an olive branch or come to the table to negotiate to show that he understands their concerns and he’s not just shoving it down Congress’ throat,” the House aide said.

“How it comes to the floor is an important factor,” Rep. Joe Crowley (D-N.Y.) said. “I think the White House should be listening. If Colombia means that much to him, they should be looking to work with the Speaker or else they risk the prospect of seeing this go down.”

Rep. Artur Davis (D-Ala.) also warned the administration not to force a vote without reaching a deal with Democrats. “It would be a mistake for the administration to push for a vote that it can’t win,” he said. “It’s going to have to have bipartisan leadership.”

But the administration clearly is getting frustrated, and feels that it has moved several times to accommodate Democratic concerns.

“We’ve given them so many olive branches we’ve almost given them an olive tree,” the official said.