"The FTAA has stalled, I agree," the US president said, referring to talks on the Free Trade Area of the Americas, which failed to yield a hoped-for agreement by early 2005 after getting bogged down in disagreements.
But Bush - who leaves Thursday for Argentina, Brazil and Panama - said he hoped to enlist Brazil to put pressure on Europe to cut agricultural subsidies and make progress in getting World Trade Organisation talks back on track.
"The Doha round really trumps the FTAA as a priority, because the Doha round not only involves our neighbourhood, it involves the whole world," he told a small group of reporters in a preview of his trip.
Bush said he spoke to Brazilian President Luiz Inacio Lula da Silva by telephone Monday to set the stage for his visit and "thanked him for the spirit of co-operation on the Doha round."
"Brazil is a very important player in Doha. It commands the respect of not only the United States and the EU, but also other countries which may or may not follow its lead," he said. "When Brazil speaks, people listen carefully."
"Both of us were somewhat disappointed in the EU response," to proposals to slash agricultural subsidies, said Bush.
"It's important for the world, not only Brazil and America, but for everybody else, that Doha move forward, and there is a spirit of co-operation between Brazil and the United States to see if that can't get done.
Under pressure from such trading heavyweights as the United States, Australia, Brazil and India, the European Union last week offered to slash import duties on farm produce in a range of 35 to 60 percent. Its previous proposal had called for cuts ranging from 20 to 50 percent.
The United States quickly deemed the offer inadequate, a position echoed Monday by the Cairns Group of 17 major food importers, notably Australia, Brazil, Canada and South Africa.
The 148 governments in the WTO are struggling to prepare for a December conference in Hong Kong, where they hope to approve the broad outlines of a multilateral accord cutting customs duties, subsidies and other barriers to commerce.
The December session is seen as pivotal to the success of the Doha round of trade talks, launched with great fanfare in 2001 in the Qatari capital and which has foundered ever since.
The WTO aims to start drafting documents for the Hong Kong meeting by mid-November.