Despite President Bush's tough line on Cuba, support for trade sanctions is crumbling in Congress, with anti-Castro activists struggling to preserve an embargo that has lasted more than 40 years.

"We're working hard and we know the odds are against us. It's like David vs. Goliath," said Cuban-born Rep. Ileana Ros-Lehtinen, R-Fla.

The House in late July approved proposals by two Republican lawmakers that, while leaving the embargo in place, would effectively ease travel and trade restrictions. The Senate is considering similar changes.

Last week, House Majority Leader Dick Armey told reporters in Kansas that the United States needs access to Cuban markets. If economic sanctions continue for another year, he said, "it will be the last year they last."

His comments dealt a blow to pro-embargo lawmakers who were counting on Armey to use his office to derail efforts to weaken the sanctions.

"I think because he is an economics professor, he should know better than to pump money into a failed, totalitarian regime," Ros-Lehtinen said. Armey, who is retiring from Congress this year, once chaired the University of North Texas' economics department.

If the changes get through Congress, pro-embargo lawmakers have a big ally in Bush, who has threatened a veto. Bush has had strong support from anti-Castro Cubans in Florida and his brother Jeb is seeking re-election there as governor.

But a veto would have consequences beyond Cuba. The proposals to ease the embargo are part of a Treasury and Postal spending bill. A veto would affect billions of dollars of unrelated programs.

"We know we're asking the president for a lot," Ros-Lehtinen said.

The embargo is intended to force democratic changes on Fidel Castro's communist island. It prohibits most business dealings with Cuba and limits travel to certain categories of visitors, including relatives of Cubans, researchers and working journalists.

For many years, liberal Democrats were practically the only opponents of the embargo, considering it ineffective and too harsh on Cuban citizens. But after the Cold War, with Cuba seen as less of a threat to the United States, some conservative lawmakers became uneasy about government-imposed travel restrictions. And farm state Republicans saw Cuba as a potentially lucrative market for agricultural products.

Congress loosened the embargo in 2000 to allow the sale of agricultural products on a cash-only basis. Cuba has since become the United States' 54th largest agricultural export market, importing products from 30 states, said John Kavulich of the U.S.-Cuba Trade and Economic Council.

"The issue of Cuba has shifted from being one of politics to being one of commerce, has shifted from being conservative vs. liberal and has shifted from Democrat vs. Republican," Kavulich said.

Pro-embargo lawmakers can no longer count on the rock-solid Republican support they once enjoyed.

"The coalition of the traditional leftists, big business and farm states is a difficult coalition," said Steve Vermillion, an aide to Rep. Lincoln Diaz-Balart, R-Fla.

Last year, the House voted to prohibit the Treasury Department, which oversees the embargo, from enforcing the travel ban for a year. The provision, sponsored by Rep. Jeff Flake, R-Ariz., was dropped in the name of national unity after the Sept. 11 attacks. But it was included in the 2003 Treasury spending bill approved last month.

Another Flake proposal approved by the House would lift the $1,200 a year cap on what Cuban-Americans can send to relatives in Cuba. And a provision by Rep. Jerry Moran, R-Kan., would allow U.S. private financing of food and medicine sales.

Ros-Lehtinen said these proposals passed because of heavy spending by lobbyists.

"Money talks," she said. "Those people are voting because they know where the money is."

But Wayne Smith, a former U.S. diplomat and longtime embargo opponent, said lawmakers recognize that the embargo has failed.

"It's not rational. It doesn't serve its purpose," he said.

Even if these provisions are approved, their effect is uncertain. Kavulich said that most travel to Cuba still would be illegal -- only Treasury wouldn't be allowed in 2003 to penalize travelers who violate the ban.

If lawmakers allow Treasury in future years to enforce the travel ban, it could go after people who traveled illegally in 2003 -- or the companies that had arranged their trips.

"Few if any U.S. companies would alter the manner in which they conduct transactions with Cuba and travel to Cuba because of the potential liability," he said.