The House vote, expected in July, on the Central America Free Trade Agreement is certain to be close, but supporters expressed new confidence Thursday after a 54-45 vote in the Senate.
The Senate win "was a huge momentum builder," U.S. Trade Representative Rob Portman said, noting that only a few weeks ago analysts were saying the agreement was in deep trouble.
Since then, the Bush administration has turned up the heat, with President Bush personally lobbying lawmakers and his trade officials dangling concessions on labor rights and sugar, the agreement's two most contentious issues.
Ten Democrats joined 43 Republicans and one independent to vote in favor of the agreement.
In a statement following the vote, Mr. Bush said the agreement would be "good for American workers, good for our farmers and good for small businesses" and "help increase sales abroad and job creation at home.
"The agreement is also a strong boost for young democracies in our own hemisphere, whose success is important for America's national security and for reducing illegal immigration," the president said.
"Senate passage of the Central America free trade legislation is a definite win for the Administration, although getting it through the House will be tough because of strong opposition by labor and immigration groups," CBS News Foreign Affairs Analyst Pamela Falk said.
"This is not the hemisphere-wide free trade agreement that the President set out to achieve, but it is a slice of the pie that the Administration has determined, full-throttle, that it will promote," Falk said.
CAFTA would further open a market of 44 million people by eliminating trade barriers to U.S. manufactured and farm goods, protecting trademarks and other intellectual property and establishing legal frameworks for U.S. investment. Last year the region purchased about $15 billion worth of U.S. goods.
The administration says it is also an indispensable step toward far broader free trade agreements with other Western Hemisphere nations and under the auspices of the World Trade Organization.
In the House, supporters will go up against a strong majority of Democrats, who argue that inadequate worker rights provisions in the agreement will lead to labor abuses, lawmakers from sugar beet and sugar cane-growing areas, and others who link free trade to America's soaring trade deficits.