MIAMI — Republican John McCain, speaking to a raucous crowd on Cuba's independence day, attacked Democrat Barack Obama for saying he would meet with President Raul Castro and called Obama a "tool of organized labor" for opposing a Latin American trade deal.

For a second day, McCain criticized Obama for saying, in a debate last year, that as president he would meet with the leaders of Cuba, Iran and Venezuela without preconditions.

McCain insisted such a meeting could endanger national security, sounding a theme that is likely to persist until the November general election.

The Arizona senator recalled the ridicule President Carter faced in 1979 when he kissed Soviet leader Leonid Brezhnev during the signing of an arms treaty.

"Carter went over and kissed Brezhnev, remember?" McCain said in Miami. "So it's dangerous; it's dangerous to American national security if you sit down and give respect and prestige to leaders of countries that are bent on your destruction or the destruction of other countries. I won't do it, my friends."

Obama protested that McCain was distorting his position and said he would try to lay ground rules for such a meeting. "John McCain likes to characterize this as me immediately having Raul Castro over for tea," he said on CNN.

"What I've said is that we would set a series of meetings with low-level diplomats, set up some preparation, but that over time, I would be willing to meet and talk very directly about what we expect from the Cuban regime," Obama said.

Last July, Obama answered unequivocally, "I would," to the question of whether he would meet, without precondition, with leaders of Iran, Syria, Venezuela, Cuba and North Korea.

McCain, on Monday in Chicago, raised the specter of a President Obama meeting with Iranian President Mahmoud Ahmadinejad. He said Obama displayed inexperience and reckless judgment in his willingness to talk with a sponsor of terrorism.

Although Obama himself has not previously disputed assertions that he meant he'd meet with Ahmedinejad, the Illinois senator seemed to backtrack yesterday when he told CNN he didn't necessarily mean he would meet with Ahmadinejad himself.

"I think this obsession with Ahmadinejad is an example of us losing track of what's important," Obama said. "I would be willing to meet with Iranian leaders if we had done sufficient preparations for that meeting. Whether Ahmadinejad is the right person to meet with right now, we don't even know how much power he is going to have a year from now. He is not the most powerful person in Iran."

Obama insisted the U.S. needs tough but direct diplomacy, like that employed by Presidents Kennedy and Reagan in negotiating with the Soviet Union in its day, and he blamed McCain and Bush for an Iraq war that he said has increased the threat from Iran.

Yesterday, dozens of people at McCain's town-hall style forum booed as he raised the notion of a meeting with Castro, and they gave McCain a standing ovation when he said that, as president, he would pressure Castro to release political prisoners unconditionally, schedule internationally monitored elections, and legalize political parties, unions and free media.