The centerpiece of President Bush's foreign trade agenda, the Central American Free Trade Agreement (search), is likely to come to a vote in the House as early as Wednesday, but the future of the free-trade deal appears very uncertain.

Click in the box to the right to watch a report by FOX News' Brian Wilson.

Bush was on Capitol Hill Wednesday morning to push for the deal's passage. Vice President Cheney was also expected to head to Congress for meetings with lawmakers.

Bush will attempt to twist the arms of fellow Republicans who are now wavering in their support for CAFTA, an agreement signed by the administration and the governments of Costa Rica, El Salvador, Guatemala, Honduras, Nicaragua and the Dominican Republic last year.

Last month, the Senate approved the measure, but some House members are not convinced.

Bush has said he believes the agreement between the United States and the six Latin American nations will level the playing field when it comes to trading commodities like sugar and textiles. House Republican leaders agree.

"This issue is important to the American people. Let's face it. Opening foreign markets is good for American workers and it's good for American business. And we all know that when business does well, jobs are created," House Speaker Dennis Hastert (search) of Illinois said at a news conference with Commerce Secretary Carlos Gutierrez and representatives from pro-CAFTA Hispanic groups.

House Democrats, who traditionally oppose such free trade agreements, are also feeling sore elbows after getting their arms twisted in the other direction by labor unions. House Minority Leader Nancy Pelosi (search) received a letter signed by 20 powerful union bosses that says supporters of the bill will face "real and measurable consequences for opposing labor on this issue."

The letter, sent Monday, urges Democrats to oppose the trade deal or risk alienating unions.

"The stakes are too high for the workers of America," reads the letter. "We cannot and we will not give any Democrat a pass on CAFTA."

Click here to read the union leaders' letter (pdf file).

Apparently getting the message, Pelosi said Tuesday that more than 90 percent of House Democrats are voting against the bill.

Opponents note that the previous free-trade deal with Canada and Mexico, the 1994 North American Free Trade Agreement, has not been good for American workers.

"CAFTA is an absolute failure on every count," said Rep. Barbara Lee, D-Calif. "We have learned from 10 years of failed NAFTA policies and we cannot go back and repeat those mistakes."

"We know the truth — that the promises of CAFTA are just empty rhetoric," said Rep. Jan Schakowsky, D-Ill.

In an effort to find votes for CAFTA, the White House and GOP leaders argue that a more prosperous Central America will help shore up U.S. national security by cementing democracies in the region.

"There's nothing like a stable society to fight terrorism and strengthen democracy, freedom and rule of law," Hastert said.

Officials appear to be having some success by making promises and cutting side deals on trade issues. Democrats say they are also not pleased about that.

"CAFTA supporters have resorted to toothless side deals and strong-arm tactics because they know this agreement cannot pass on its merits," said Rep. Sherrod Brown, D-Ohio.

"There's deal-making that goes on in the United States Congress," countered White House spokesman Scott McClellan. "This is a free-trade agreement that will help level the playing field for American producers and American farmers and for our products."

The leaders of all six CAFTA nations recently visited members of Congress and spoke to Hispanic and other groups to promote the deal. Whether their arguments were in vain will be determined this week. The House vote is expected before Congress leaves Friday for its six-week summer break.

The Associated Press contributed to this report.