President Bush, facing a battle to win congressional approval of a new free-trade agreement in an era of soaring trade deficits, is getting lobbying help from an unusual source — the presidents of six Latin American countries.

In fact, historians believe this is the first time the leaders of six foreign countries have descended on Capitol Hill to stage a lobbying blitz.

"We haven't been able to come up with anything comparable to this," said Senate historian Donald Ritchie. "It is unusual for any head of state to lobby Congress, but even more unusual for a half-dozen to do it."

The presidents of the Dominican Republic and the five Central American countries of Costa Rica, El Salvador, Guatemala, Honduras and Nicaragua, planned to walk the halls of Congress on Wednesday to seek support for the Central American Free Trade Agreement (search).

Meetings were scheduled with Senate Majority Leader Bill Frist and House Speaker Dennis Hastert as well as key lawmakers on trade issues.

Even with the reinforcements, CAFTA will have to 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 and a string of record trade deficits.

The administration is promoting the deal as a way to open new markets for U.S. farm goods and manufactured products and help a region that two decades ago was engulfed in civil wars.

At a reception honoring the presidents at the U.S. Chamber of Commerce on Tuesday night, U.S. Trade Representative Rob Portman (search) said the administration saw CAFTA as a way to help "solidify democracy in a critical region of our hemisphere."

Addressing members of Congress on behalf of the visiting presidents, Nicaragua's President Enrique Bolanos said, "I know you are going to vote for CAFTA because you care for your nation and also your neighbors."

Honduran President Ricardo Maduro was absent, stranded by bad weather in North Carolina, Portman said.

The foreign leaders' visits will end with a meeting with Bush on Thursday at the White House at a CAFTA rally in which the administration hopes to demonstrate Bush's strong commitment to getting the agreement through Congress.

Even before the presidents arrived in Washington, the administration had them hopscotching the country talking to governors, participating in rallies and meeting with newspaper editorial boards.

Salvadoran President Tony Saca touched down in Los Angeles, San Diego and Santa Fe, N.M., while three other presidents — Bolanos, Maduro and Oscar Berger of Guatemala — participated in an event Monday at the Port of Miami with Florida Gov. Jeb Bush.

Maduro said CAFTA would translate into "sustained, significant and equitable economic growth" for his country.

The congressional battle over CAFTA is shaping up as the most ferocious free trade fight since the North American Free Trade Agreement (search) linking the United States, Canada and Mexico was approved more than a decade ago.

Opponents contend CAFTA will promote the movement of U.S. manufacturing plants to the six low-wage countries to make goods for duty-free shipment back into the United States, just as NAFTA promoted a similar movement of jobs to Mexico.

"America's workers don't need more bad trade deals. America's workers don't need more corporate giveaways," AFL-CIO Secretary Treasurer Richard Trumka said at an anti-CAFTA rally Tuesday on Capitol Hill.

The CAFTA deal also faces opposition from U.S. sugar producers. They are upset that the deal will allow increased imports of sugar from the Latin American nations.

The administration scored at least a partial victory Monday with the announcement that one prominent textile trade group, the National Council of Textile Organizations (search), is supporting CAFTA. The group says the deal will help U.S. textile manufacturers, allowing them to sell more textiles to CAFTA countries, where the fabric will be made into finished goods to be shipped back to the United States.

Another major textile group, the American Manufacturing Trade Action Coalition (search), remained opposed to CAFTA, saying it will cost the United States jobs.