MERIDA, Mexico -- President Bush ended his Latin American tour Wednesday vowing to beat back "protectionist sentiments" in the USA and win over more of his own party for an overhaul of immigration laws.

With Mexican President Felipe Calderon at his side, Bush said efforts to tighten the U.S.-Mexican border over the past year should make opponents "more open minded" about backing a program for more foreign "guest workers."

"My mood is optimistic because the mood in the Congress seems like it has changed," Bush said.

Sen. Tom Coburn of Oklahoma and some other Republicans have objected to provisions of a bill sought by Bush that would allow more guest workers and put some illegal immigrants in the USA on a path to citizenship. Coburn and other critics call the citizenship plan "amnesty," but Bush said he would insist that those applying for citizenship earn the right.

Bush also said a key to getting an immigration bill from Congress could be Sen. Edward Kennedy, D-Mass., whom he praised as a good negotiator. Kennedy is leading a renewed effort to get a comprehensive immigration bill, opposed last year by members of Bush's own Republican Party.

Immigration was a key topic during two days of meetings with Calderon and at other stops on Bush's five-nation trip. Calderon and other Latin leaders have criticized Bush's border-security efforts, included legislation signed last year authorizing 700 miles of fencing on the U.S.-Mexican border.

"The border should bring us together and not separate us," Calderon said through an interpreter.

Calderon endorsed Bush's comprehensive approach to overhauling immigration laws, saying it would help Mexico's efforts to develop its own economy.

The Mexican leader said he has relatives working in the USA but did not say whether they were in the country legally.

"These are people who work and respect that country," he said. "They pay their taxes."

Bush and Calderon also discussed trade rules for Mexican corn and beans, more intelligence sharing on international drug gangs, and new border crossing points to help speed up the transit of legal immigrants and products.

Bush said recent efforts to step up border enforcement address concerns in the USA that existing laws be enforced. He added that immigration is "sensitive" because it is "an issue that people can use to inflame passions."

The immigration issue followed Bush on his goodwill trip, which included stops in Brazil, Uruguay, Colombia and Guatemala. Bush said one of the reasons for his trip was "to remind people in this important part of the world that the United States cares deeply about the human condition."

Protesters greeted Bush at each of his stops, many in opposition to the Iraq war.

Venezuelan President Hugo Chavez, a frequent Bush critic, shadowed his U.S. counterpart and held his own Latin American tour. Chavez argued that U.S. trade policies benefit the wealthy at the expense of the poor.

Armand Peschard-Sverdrup, director of the Mexico Project at the Center for Strategic and International Studies in Washington, said Bush did "very well" in his efforts at public diplomacy, whether it was praising the beef in Uruguay, loading boxed lettuce in Guatemala or touring Mayan ruins in Mexico.

"He's trying to project a more likable image of himself," said Peschard-Sverdrup, and "counter the U.S. image as an aggressor."