President Bush (search), faced with stiff opposition to the free-trade pact he wants with Central American and Caribbean nations, on Thursday portrayed its passage as crucial to America's security and commitment to democratic change in the neighborhood.

"By transforming our hemisphere into a powerful free trade area, we will promote democratic governance, human rights and economic liberty for everyone," Bush said, with presidents of the Dominican Republic and the five Central American countries of Costa Rica, El Salvador, Guatemala, Honduras and Nicaragua at his side at the White House. "The United States was built on freedom and the more of it we have in our backyard, the freer and safer and more prosperous all of the Americas will be."

The pact, signed by Bush last May, needs the approval of Congress. But it is in trouble there, especially in the House where Democratic opponents have been joined by Republican lawmakers from sugar- and textile-producing districts.

With opponents claiming they have enough votes to kill the measure, the battle is shaping up as the most ferocious free-trade confrontation in Congress since the debate over the North American Free Trade Agreement (search) more than a decade ago. That 1994 pact links the United States, Canada and Mexico.

The event with Bush in the Rose Garden was an attempt to change the momentum toward the measure. The six presidents spent Wednesday walking the halls of Congress to lobby for the pact.

Critics claim more free-trade pacts are not a good idea in time of soaring trade deficits (search). Bush also must overcome opposition from U.S. labor unions, sugar farmers and groups upset with more than 3 million lost manufacturing jobs over the past five years.

The president appealed to opponents' economic and patriotic interests as he tried to drum up support.

He said the deal would represent an improvement over the current situation for American workers, businesses and farmers by leveling the playing field on tariffs. Most Central American exports, he said, now already enter the United States duty-free, while American products exported south are subjected to hefty tariffs.

The free-trade pact also would open a market of 44 million consumers for U.S. farm products and manufactured goods, he said. And, Bush argued, it would make it more likely for factories to remain in Central America, where they often use American materials, rather than relocate to Asia.

Bush's most passionate appeal involved the need to support "small nations ... making big and brave commitments" to openness in governmental and economic affairs.

"The Central America and Dominican Republic Free Trade Agreement presents us with an historic opportunity to advance our common goals in an important part of our neighborhood," he said. "By passing this agreement, we would signal that the world's leading trading nation was committed to closer partnership with countries in our own backyard, countries which share our values."