June 1 (Bloomberg) -- John McCain is betting that he can revive his reputation for straight talk, and his campaign, by challenging his rivals for the Republican nomination on the issue of immigration.

McCain, 70, is championing legislation that the other contenders, and many of the party's core voters, denounce as an amnesty program for illegal immigrants. While some Republican strategists say this strategy risks political suicide, the Arizona senator said he is following a contrarian script that has served him well.

``I've taken on other political risks'' and ``almost all of the time when I do what I believe is right it turns out OK in the end,'' McCain said in a May 29 telephone interview.

McCain plans to deliver a speech on immigration in Miami on June 4, one day before the next Republican debate. Brian Jones, his spokesman, said McCain will ``likely draw contrasts with some of his opponents who are criticizing the legislation but not offering any solutions.'' In the past two weeks, McCain has addressed the issue on eight talk shows and six conference calls with reporters in early primary states.

Immigration is ``incredibly emotional'' for about a third of Republican voters, McCain said. ``You've got an intensity level that polls don't measure.''

McCain is taking aim at his three main rivals for the Republican nomination, former Massachusetts Governor Mitt Romney, former New York Mayor Rudy Giuliani and former Senator Fred Thompson of Tennessee, who all oppose the bill, which could be up for a Senate vote this month.

Romney

In the interview, McCain reserved his sharpest criticism for Romney, 60, whom he said tailored his immigration message to different crowds. ``Eleven months ago, he articulated the principles that are embodied in this bill,'' McCain said. ``He certainly has changed positions.''

McCain said Romney recently criticized the plan in South Carolina, but ``his rhetoric changed rather significantly'' a few days later in heavily Hispanic Florida, when he ``found out that feeling was a little bit different down there.''

McCain also criticized Giuliani, 63, who last week condemned the immigration bill as a ``hodgepodge,'' and Thompson, 64, who has signaled he may announce his candidacy soon and said May 17 that the immigration bill should be scrapped.

Those kinds of statements, McCain said, are ``very disappointing.'' He added: ``It's easy to just say no.''

`Wrong, Again'

Romney's spokesman, Kevin Madden, said McCain had proved he is ``wrong, again'' on immigration. The bill would provide a ``blanket legal status'' that Romney believes is the ``wrong approach,'' Madden said.

The bill, which has support from President George W. Bush and many Democrats, would give illegal immigrants a chance for permanent residency and eventual citizenship. It would also create a temporary-worker program and tighten border security.

McCain's support for immigration stands in contrast to his strategy for winning the nomination thus far. Initially the frontrunner, McCain has spent much of this year appealing to Republican stalwarts with his support of the Iraq war and by reaching out to social conservatives.

David Carney, a Republican strategist, said McCain is trying to recapture some of the maverick aura he had as a candidate in 2000. ``When things aren't going well the first thing a candidate does is revert back to their natural habitat,'' Carney said. ``He's trying to get some of the luster back.''

`Don't Agree With You'

McCain acknowledged that this approach has served him well in the past. ``A couple of my supporters have said `look, the reason why I support you is because even though I don't agree with you, you stand up for what you believe in,''' he said.

Still, Ed Rollins, a Republican consultant and former campaign manager for Ronald Reagan, said McCain is taking a major political risk with his position on immigration.

``He's not going to be convincing any Republicans that this is a good bill,'' Rollins said. ``This is going to hurt him.''

Since May 18, when McCain stood with Democratic Senator Edward Kennedy of Massachusetts to announce the bipartisan deal on immigration, traders have lowered the odds that he will clinch the nomination. Two weeks ago, traders on Intrade, an online electronic exchange based in Dublin, put McCain's odds at about 28 percent; as of May 31, the odds were about 17 percent.

McCain is betting he will eventually get credit for his stance. He cited a New York Times/CBS News poll conducted May 18 to May 23 that found that 66 percent of Republicans and two- thirds of all Americans favor the bill before Congress.

``The majority of the Republican Party supports this position,'' he said. ``But there's such strong feeling from those who oppose it, so you don't know.''

For now, being at odds with the competition is a position he appears to enjoy.

``There are several other issues where we are in disagreement,'' said McCain, citing the May 15 Republican debate in which Giuliani and Romney hypothetically endorsed the use of torture to obtain information about an imminent terrorist attack. ``Every one of them wants to torture people. It's amazing.''

To contact the reporter on this story: Heidi Przybyla in Boston at hprzybyla@bloomberg.net

Last Updated: June 1, 2007 00:05 EDT