The call from President Bush came around 7 a.m. yesterday to the home of U.S. Trade Representative Rob Portman. Just hours earlier, the House of Representatives approved the Central American Free Trade Agreement, and the president wanted to offer his congratulations.

But pleased as he was by the president's gesture, Portman didn't have a lot of time to celebrate yesterday. When the call came he was in the midst of packing his bag for an early afternoon flight to Geneva, the headquarters of the World Trade Organization.

The scene captured the state of the Bush administration's efforts to tear down trade barriers around the world. Portman and his administration colleagues may be flush with victory in their battle for CAFTA, the most fiercely contested trade accord in the past decade. But they still face enormous challenges in securing agreements of major economic significance, especially from global negotiations in the WTO.

Portman's trip to Geneva is intended to revitalize the current WTO talks, known as the Doha round. Hopes were high when the talks began in 2001 that they would produce a far-reaching agreement by the WTO's 148 member nations to slash tariffs and government subsidies, especially in the farm sector, which could give a big boost to agricultural exporters including the United States and many poor nations. But negotiations broke down in recent days with countries still far apart over the farm issue, hurting chances for a breakthrough that would put the talks back on track before a meeting scheduled for December.

Meanwhile, CAFTA's critics are trumpeting the closeness of the House vote as evidence that the free-trade movement is running out of political steam. The agreement passed just after midnight, 217 to 215, and only after Republican leaders held the vote open for an hour, long past the usual 15-minute limit, so they could round up reluctant members of their party.

"Compared to the vote a decade ago on NAFTA, which carried by a margin of only thirty-four votes, this vote was even more razor-thin," Rep. Marcy Kaptur (D-Ohio) said in a written statement yesterday. "It barely crawled across the finish line." Her conclusion: "Our resolve contributed to strengthening the broad public support that grows each year for changing these flawed agreements."

Interviewed yesterday in his office before heading to the airport, a tired but cheerful Portman offered a much more optimistic assessment of the CAFTA vote and the administration's trade agenda.

"Yeah, it was a narrow victory, and we had to get Republicans to vote yes even though they feel it will hurt them politically," said Portman, who was a Republican House member from Ohio before becoming trade representative three months ago. "But given the forces arrayed against us and given the politics of trade, it was a significant victory for those who believe we ought to be opening markets."

Free-trade deals with Australia, Morocco and Singapore sailed through Congress with relative ease in recent years, but critics viewed CAFTA as "the agreement to stop, and they pulled out all the stops to do it," Portman said. That is because the extreme poverty and questionable labor-rights records of Central American countries were a red flag to people who fear that free trade with such nations will lead to lower living standards. But even though the opponents had support from powerful lobbies such as the sugar industry, they fell short.

Passing CAFTA should be "very helpful, giving us some momentum" in the WTO talks, Portman said. "The alternative would have suggested to people that the United States isn't able to ratify or approve trade-opening agreements," which would have discouraged trading partners from offering concessions in future negotiations. Foreign governments will be "impressed that we prevailed," he said.

Momentum for the WTO talks may be the most significant economic result of CAFTA's passage. The U.S. economy is unlikely to be affected noticeably by trade with countries -- Guatemala, Honduras, Costa Rica, Nicaragua, El Salvador and the Dominican Republic -- whose collective gross domestic product is less than 1 percent of U.S. national output.

Portman's genial but intensive performance during the clash over CAFTA won him high marks even from opponents of the deal. "His effort and shoe leather clearly made a difference," said Bill Frymoyer of the trade law firm Stewart and Stewart, who lobbied for an anti-CAFTA client and was once an aide to former House Democratic leader Richard A. Gephardt. "He knows the Congress, he knows the pressure points, he knows how to get it done."

It is another matter entirely, though, whether Portman's skills on Capitol Hill will translate into success at the WTO in overcoming resistance from countries such as Brazil, India, Egypt and France.

"I'm patient. I know this is tough, to get 148 countries to agree on anything," Portman said. "Are we as far along as people had hoped? No. But have we breathed life into the process? Yes. . . . I'm still optimistic that we can make progress toward the Doha goals."

As for the partisan rancor over CAFTA, Portman said he would aim to change the atmosphere in the trade debate.

"Only 15 Democrats voted for it, but I talked with at least twice that many, and almost every conversation ended with, 'I want to work with you on the next one,' " Portman said. "Having come from Congress, I want to reach out, and begin to rebuild what was once a fairly robust consensus."

U.S. Trade Representative Rob Portman is headed to the World Trade Organization in Geneva. Portman, right, and Irving Guerrero, the Honduras trade minister, discussed labor and environmental issues at a July 19 news conference.