The only speech of the president's three-nation tour of Central and South America focused on the importance of safeguarding democratic ideals in the region.
He said the people of Latin America have defied dictators to win their liberty, and he warned there are some who want toset back the clock.
Mr. Bush said they must now choose between two competing visions. "One offers a vision of hope that is founded on representative government, integration into the world community, and a faith in the transformative power of freedom in individual lives," said the president. "The other seeks to roll back the democratic progress of the past two decades by playing to fear, pitting neighbor against neighbor, and blaming others for their own failures to provide for their people."
The president named no names. But the comments were apparently a reference to either Cuba's Fidel Castro or Venezuelan President Hugo Chavez, a fiery critic of the Bush administration. "Some today suggest that democracy has outlived its usefulness," said Mr. Bush. "They have misread history."
In the address, Mr. Bush also praised Brazil's role in helping other countries seeking freedom and social justice. And he promised to work with President Lula to ease differences on trade.
Brazil was one of five nations at the just-ended Summit of the Americas to oppose U.S. calls for negotiations on a hemispheric free-trade agreement. Mr. Bush said he made his case once again when he met face to face with the Brazilian leader.
"He has got to be convinced, just like the people of America must be convinced, that a trade arrangement in our hemisphere is good for jobs, is good for the quality of life," said President Bush.
President Lula is far to the left of President Bush on the political spectrum. But as he stood with Mr. Bush on the grounds of Brazil's presidential retreat, he said relations between their two countries are far better than many expected when he took office in 2003.
"When I was elected president, there were those who foresaw the deterioration of relations between Brazil," said Mr. Lula. "They were roundly mistaken."
Earlier President Bush answered questions from a group described as young leaders. One man, a university professor, asked Mr. Bush about the tens of thousands of demonstrators who showed up Friday at the Summit of the Americas in Mar Del Plata, Argentina.
Mr. Bush said they were exercising freedom of speech and expression - one of the core elements of democracy. "I expect there to be dissent," said the president. "That is what freedom is all about. People should be allowed to express themselves. And so what happened in Argentina happens in America. That's positive."
There were also protests in Brasilia during the president's brief visit, but they were small in comparison to those seen in Argentina. From Brazil, Mr. Bush travels to Panama - the last stop on his three-nation visit to Central and South America.