American lawmakers on Wednesday voted to ratify long stalled free-trade agreements with Colombia, Panama and South Korea in what is heralded as the most significant expansion of trade relations in nearly two decades.

Although the trade accords with Colombia and Panama, negotiated by the Bush Administration, are unlikely to have a significant economic impact, the agreement with the Republic of Korea could boost American exports by up to $12 billion per year and create as many as 280,000 jobs in the United States, according to an assessment by the International Trade Commission, an independent federal advisory body. Other studies have suggested a net job gain of 70,000.

President Barack Obama hailed the vote as a victory for the American economy. “Tonight’s vote, with bipartisan support, will significantly boost exports that bear the proud label ‘Made in America,’ support tens of thousands of good paying American jobs and protect labor rights, the environment and intellectual property,” he said.

The president’s own party, however, had stalled ratification of the trade agreements as labor unions claimed that they would incur major job losses in the United States. The administration renegotiated part of the deal with Seoul last year to protect American automakers against immediate Korean competition.

Opposition Republicans had urged ratification of the trade deals but were opposed to expansion of a compensation program that finances benefits and retraining to workers who lost their job as a result of free-trade pacts.

Many Republicans voted for expansion of trade adjustment on Wednesday nevertheless while a significant number of Democratic lawmakers voted against the trade deals altogether.

The vote came on the eve of a visit by President Lee Myung-bak of Korea who is expected to address a joint session of Congress on Thursday afternoon.