By FRANK DAVIES AND NANCY SAN MARTIN

  WASHINGTON - Bowing to a veto threat from President Bush, Republican leaders in Congress have killed an effort to ease U.S. sanctions on Cuba for the fourth year in a row, despite the wide support the measure enjoyed on Capitol Hill.

  The decision, made at a late-night meeting Wednesday, quietly to kill a measure that would have effectively lifted the ban on travel to Cuba overrode strong anti-ban votes in the House and Senate this fall but left foes of U.S. policy on Cuba frustrated, angry and scrambling for a new strategy.

  Sen. Richard Shelby, R-Ala., and key House Republicans told other members of a House-Senate conference committee at the meeting that the provision to end the ban, part of a $90 billion Treasury-Transportation spending bill, had to come out.

  Given Bush's warning that he would veto any change in the embargo on Cuba, ''there is no alternative other than to remove the Cuba travel provision'' from the bill,
  Shelby said.

  LEADERS AGREED

  Staff members who worked on the issue said House Majority Leader Tom DeLay, R-Tex., and Senate Majority Leader Bill Frist, R-Tenn., supported the decision to strip the Cuba provision from the bill before the conference committee even met.

  The decision was made even though the Senate had voted 59-36 and the House 227-188 on virtually identically worded measures denying the Treasury Department any funds to enforce the travel ban, which applies mostly to tourist trips.

  Rep. Ileana Ros-Lehtinen, a Miami Republican who lobbied Frist hard on the issue, along with Reps. Lincoln and Mario Díaz-Balart, credited DeLay with killing the language.

  ''He has been a wizard at making sure members understood that the president would veto the hard work they put into this bill,'' Ros-Lehtinen said of Frist. ``And this demonstrates the muscle the president has in Congress.''

  Bush has steadily threatened to veto any measure that would ease U.S. sanctions on the communist-ruled island, and instead ordered stricter enforcement of the travel ban and the U.S. trade embargo against Cuba.

  SOME OPPOSITION

  Several Congress members spoke out against the decision Wednesday, but no formal vote was taken by the conference committee, which was evenly divided by the Cuba issue. Many members were more concerned with other sections of the spending bill on Amtrak subsidies, highway funds and pension provisions.

  Though the result came as no surprise, many opponents of the U.S. embargo were angered by the tactics used to block the measure.

  ''There is something out of whack with how the Cuba language was removed,'' complained Sen. Mike Enzi, R-Wyo. ``It was stripped by staffers even before members of the committee formally met. There was no vote taken. Poof, it just disappeared into the congressional ether.''

  Several Congress members grumbled that on the Cuba issue, presidential politics -- and the need for Bush to win Cuban-American votes in Florida and New Jersey next year -- trumped other issues.

  ''We will never have a rational Cuba policy as long as presidential campaigns are perceived to end in Florida,'' said Rep. Jeff Flake, R-Ariz., who sponsored the end of the ban in the House.

  In Havana, the Cuban government criticized the decision. The Ministry of Foreign Relations issued a statement saying that GOP leaders and anti-Castro activists in Miami were ``violating the rules and regulations established by the Congress itself.''

  U.S. travel to Cuba is mostly limited to Cuban Americans, humanitarian and educational groups and journalists. Backers of the travel ban say that any easing of
  restrictions would funnel more tourist dollars to a repressive government without helping average Cubans.

  Opponents of the travel ban say it is anachronistic and a failure. They also say that more U.S. visitors traveling to the island and more contacts between Americans and Cubans will help the Cuban people. Those pushing to change the policy are running out of options for this session of Congress, due to end this month. A separate bill to end the travel ban, sponsored by Enzi and Sen. Max Baucus, D-Mont., passed the Senate Foreign Relations Committee last week on a 13-5 vote, but floor action soon is unlikely.

  Jody Frisch, director of USA Engage, a coalition of 600 companies, agricultural and trade groups, predicted that support for the Enzi-Baucus bill would grow next year.

  ''We remain as committed as ever,'' Frisch said.

  But not everyone was convinced the latest setback would refuel efforts to chip away at the embargo.

  ''We don't have a lot of time left to play a game with the administration,'' because this session of Congress will end soon, said Chris Garza, trade specialist for the
  American Farm Bureau.

  ''Next year becomes very difficult to do anything on Cuba because it's an election year,'' Garza added.