John McCain has changed his mind about the president’s tax cuts and drilling for oil off the U.S. coast, but the Republican presidential hopeful says his advocacy of free trade is unyielding.

McCain said he knows he has work to do to convince voters in states losing jobs to Mexico and other countries, such as Pennsylvania where he campaigned Monday, that free-trade agreements will benefit them and their families over time.

“I have to convince them the consequences of protectionism and isolationism could be damaging to their future,” the Arizona senator said, pledging to improve programs for displaced workers and unemployment insurance if elected.

“I understand it’s very tough. But for me to give up my advocacy of free trade would be a betrayal of trust,” he said. “And the most precious commodity I have with the American people is that they trust me.”

McCain once opposed President Bush’s tax cuts for the wealthy, but now wants them to be made permanent. He was a supporter of the federal ban on offshore oil drilling, but recently said the moratorium should be lifted and states allowed to decide for themselves whether to begin drilling.

McCain on Tuesday was beginning a three-day visit to Colombia and Mexico, to bookend a trip earlier this month to Ottawa, where he talked up cross-border cooperation with Canada on economic issues, especially trade.

He is a strong supporter of NAFTA, the North American Free Trade Agreement, among the U.S., Canada and Mexico.

When McCain went to Canada, Democratic presidential rival Barack Obama suggested he went to promote the agreement rather than stay home and defend his views in places like Ohio and other states where NAFTA is blamed for shifting millions of manufacturing jobs to other countries.

Obama is a critic of NAFTA and other free trade deals, and the issue was a flash point in his primary campaign against Hillary Rodham Clinton. As president, he has said he would push for enforceable labor and environmental standards in the agreement and might threaten to withdraw completely.

McCain insisted the trip to Latin America was not intended to be political and said he would not criticize Obama directly while abroad. He made a similar pledge when he visited Canada but took a swipe at the Democrat nonetheless, suggesting without using Obama’s name that the Illinois senator’s opposition to NAFTA was “nothing more than retreating behind protectionist walls.”

McCain was to arrive in Cartagena, Colombia, on Tuesday and meet with President Alvaro Uribe and several cabinet ministers. McCain also is a strong supporter of a proposed free-trade agreement with Colombia that is stalled in Congress. The House blocked a vote over issues that include violence against labor activists in the country.

McCain said Uribe had rescued Colombia from becoming a “failed state” and only indirectly criticized the government’s human rights record. While he said he anyone perpetuating human rights abuses in the country should be arrested and tried, he insisted the country’s struggle with the issue was no justification for blocking the proposed agreement.

In Mexico City, he planned to address illegal immigration — an emotional issue both for Hispanic voters and many conservatives.

McCain co-sponsored Senate legislation that would have allowed illegal immigrants to stay in the U.S., work and apply to become legal residents after learning English, paying fines and back taxes, and clearing a background check. The measure failed last year and McCain since has talked primarily about the importance of boosting border security, and less so about a pathway to citizenship for those in the country illegally.

In a speech last Saturday to elected Latino officials, McCain pledged that the issue will be “my top priority yesterday, today and tomorrow.”