By Jim Rutenberg and Larry Rutenberg

President Bush has portrayed his trip to Latin America this week as a ''We Care'' tour aimed at dispelling perceptions that he has neglected his southern neighbors. But fresh graffiti on streets here in Sí£o Paulo, where he landed Thursday night for his first stop, calls him a murderer. The smattering of protests and the placement of military vehicles around the city, South America's largest, also present an alternate interpretation of his visit: as a clash between the open capitalism that Mr. Bush espouses and the socialist approach pushed by leftist leaders who have grown in power and popularity.

And as the administration prepares to use the president's five-nation tour to highlight a new ethanol development deal with Brazil, the most efficient producer of the fuel, and American health care and education programs elsewhere, much of the tour attention is focusing on what may best be called ''the Rumble on the River.''

President Hugo Chávez of Venezuela, Mr. Bush's chief nemesis in the region, will be leading a protest against him in Buenos Aires, as Mr. Bush arrives Friday in Montevideo, Uruguay, across Rio de la Plata from Argentina. ''Our planes will almost cross paths,'' Mr. Chávez said this week, though he denied any intention to sabotage Mr. Bush's visit. In interviews with Latin American reporters this week, Mr. Bush played down Mr. Chávez's planned rally, telling one group on Tuesday: ''I go a lot of places and there are street rallies. And my attitude is, I love freedom and the right for people to express themselves.''

Whether inadvertently or not, though, Mr. Bush irritated Mr. Chávez with a speech on Monday in Washington, in which he said Simón Bolivar, the hero of South America's independence struggle and Mr. Chávez's idol, ''belongs to all of us who love liberty.'' This brought a sharp and sarcastic rejoinder from Mr. Chávez the next day.

But in spite of administration attempts to minimize the shadow cast on the visit by Mr. Chávez -- who has pushed an aggressively anti-American agenda throughout the region -- the tour itself seems at least in part geared to counter his influence. Mr. Chávez has built that influence in part by showering poor communities with money for housing and health care and by freely dispensing oil at cut-rate prices. Mr. Bush's new agreement with Brazil to increase ethanol production in the region represents a way to cut back on the influence that Mr. Chávez's oil supply gives him, while encouraging employment and economic development. And before arriving here, Mr. Bush announced a number of programs to help the poor in the region, whom he referred to, in Spanish, as ''workers and peasants.'' He promised hundreds of millions of dollars to help families buy homes and said he would dispatch a Navy hospital ship to the region to provide free health services.

In his interviews this week, Mr. Bush has repeated that the United States' aid to the region has doubled during his tenure, to about $1.6 billion annually. ''When you total all up the money that is spent, because of the generosity of our taxpayers, that's $8.5 billion to programs that promote social justice,'' including education and health, he told reporters on Tuesday.

But the view from here could scarcely be more different. In an editorial headlined ''Uncle Scrooge's Paltry Package,'' the conservative daily newspaper O Estado de Sí£o Paulo noted Wednesday that Mr. Bush's offering amounted to ''the equivalent of five days' cost of the war in Iraq, and a drop of water compared with the ocean of petrodollars in which Chávezism is navigating at full speed, from Argentina to Nicaragua.''

Some of Mr. Bush's aides said they were worried that perceptions that the United States had neglected its southern neighbors, and frustration in lower classes that had not reaped the benefits of free trade, were helping to fuel leftist movements. Stephen J. Hadley, Mr. Bush's national security adviser, said, ''Something we have not done well enough is getting out the full scope of the president's message.'' Mr. Bush told reporters that he hoped to counter Mr. Chávez's message by espousing the benefits of free trade.

Asked by a reporter about Mr. Chávez's ''so-called alternative development model'' calling for nationalization of industry, Mr. Bush said: ''I strongly believe that government-run industry is inefficient and will lead to more poverty. I believe if the state tries to run the economy, it will enhance poverty and reduce opportunity.'' He added, ''So the United States brings a message of open markets and open government to the region.'' But even Mr. Bush's Brazilian hosts seemed divided in their reaction to that message. Although President Luiz Inácio Lula da Silva will be meeting with Mr. Bush on Friday to sign the ethanol accord and is scheduled to visit him at Camp David on March 31, the leftist Workers' Party he leads has chosen to support and take part in the anti-Bush demonstrations.

The party warned on its Web site that Mr. Bush ''shouldn't count on Brazil for imperialist actions in the region.'' One essay called him ''the big boss of international terrorism,'' while another declared that Mr. Bush was ''persona non grata'' in Brazil. ''The United States in general and the Bush government in particular are brutally violent,'' wrote Valter Pomar, the party's secretary for international relations. ''We will only be free of this threat when the North American people constitute a government on the left.''

At an evening rush-hour protest in the central business district here, several thousand activists wore stickers showing Mr. Bush with a Hitler-style mustache and a swastika next to his head and the words ''Fora Bush,'' or ''Bush Out.'' With the police standing by in riot gear, antiwar protesters mixed with unionists and environmentalists, who are concerned that harvesting ethanol from sugar could hurt the Amazon. A sea of signs read ''Adolf Bush'' or ''Quit Playing With the Environment.'' Later, the Brazilian news media reported that police officers used tear gas and batons on protesters who were throwing rocks and struggling with the officers, sending hundreds of demonstrators running through the streets of Sí£o Paulo. There were no major injuries reported.