BY PABLO BACHELET

Setting up an election-year showdown with Democrats, President Bush on Monday sent Congress a contentious free trade agreement with Colombia for approval.

The move represents a high-risk gamble as many Democratic lawmakers and presidential aspirants Sens. Hillary Clinton and Barack Obama oppose a deal rejected by U.S. organized labor, which contends too many union members are murdered by armed groups. Republican presidential hopeful Sen. John McCain supports the pact.

In a ten-minute speech before signing a letter notifying Congress of his decision, Bush said the administration has held more than 400 consultations with lawmakers in an effort to reach a deal that would ensure passage for a trade deal signed 16 months ago.

Flanked by five Cabinet secretaries, Bush cast the deal as a winner for the U.S. economy and needed to promote U.S. national interest in the hemisphere. He said Colombia faced a ''hostile and anti-American regime'' in Venezuela, which is ruled by populist President Hugo Chávez.

He said conservative Colombian President Alvaro Uribe was making efforts to stop the attacks against union members and had succeeded in making the country more secure as it battled guerrilla groups.

''The stakes are high in South America,'' Bush said. ``By acting at this critical moment, we can show a watching world that America will honor its commitments. We can provide a powerful rebuke to dictators and demagogues in our backyard. We can expand U.S. exports and export related jobs. We can show millions across the hemisphere that democracy and free enterprise lead to a better life.''

Colombia, South America's second most-populous nation, already enjoys duty-free access to the U.S. market, thanks to a special arrangement that is renewed periodically. Most tariffs on U.S. exports would be cut to zero after the agreement goes into effect.

But the economics of the agreement are less controversial than the politics, as was underscored by the resignation of Mark Penn as the Clinton campaign's chief strategiest. Penn, in his capacity as CEO and president of public relations firm Burson-Marsteller, met last week with Colombian Ambassador Carolina Barco to explore ways to promote the free trade agreement.

Senate Majority Leader Harry Reid criticized Bush's decision on Colombia.

''By sending up the Colombia FTA legislation under circumstances that maximize the chances it will fail,'' Reid said, ``he will be adding one more mistake to his legacy and one more mess for the next president to clean up.''

Reid acknowledged there was ''tremendous respect'' in Congress for Uribe's achievements but that many Democrats had ``serious concerns about an agreement that creates the highest level of economic integration with a country where workers and their families are routinely murdered and subjected to violence and intimidation for seeking to exercise their most basic economic rights.''

''The government of Colombia has undoubtedly made progress on this front,'' he added, ``but the level of violence against trade unionists is still the worst in the world.''

Under legislation known as trade promotion authority, Congress has 90 legislative days to vote on the pact. Bush made it clear he will seek an agreement that would avoid a photo-finish vote that accompanies contentious trade deals. A similar agreement with six Central American and Caribbean nations passed by two votes in the House in 2005.

One possibility is providing more generous economic benefits to U.S. workers negatively impacted by trade, something Democrats want. Bush said he is ''committed to advancing'' a trade assistance bill.

In an opinion piece published Monday in the Wall Street Journal, Secretary of State Condoleezza Rice said that since 2002, the murder of trade unionists has fallen 80 percent, but she recognized problems persisted.

''Colombia is a functioning democracy,'' Rice said. ``The fact that our friend remains imperfect, and that it still faces overwhelming challenges, should lead us not to withdraw our support, but to increase it.''

Treasury Secretary Henry Paulson echoed this pitch at a speech before the annual assembly of the 47-member Inter-American Development Bank in Miami on Monday.

''Congressional approval of the Colombian free trade agreement will reinforce democracy in Latin America by showing support for a key ally, an ally who has made significant advancements to combat violence and instability,'' he said.

However, Paulson recognized a tough slog lay ahead.

``One of the many things I have learned since moving to Washington is that no trade bill is an easy bill.''