On Friday, in an otherwise unremarkable speech, Mitt Romney said he is the candidate who best represents the "Republican wing of the Republican Party." This prompted John McCain, who apparently considers Romney something of a fraud, to launch quite a tirade yesterday in New Hampshire.

"When he ran against Ted Kennedy," Mr. McCain said as dozens of people wearing Romney buttons looked on angrily, "he said he didn't want to return to the days of Reagan-Bush. I always thought Ronald Reagan was a real Republican."

He continued: "When he voted for a Democratic candidate for president, Paul Tsongas, I don't think he was speaking for Republicans. When he refused to endorse the Contract with America, I don't think he was speaking for Republicans. And when he was embracing the Democratic position on many issues of the day, I don't think he was speaking for Republicans."

As Mr. McCain spoke, his voice became pitched with indignation.

"So you'll understand why I'm a little perplexed when Mitt Romney now suggests that he's a better Republican than me, or that he speaks for the Republican wing of the Republican Party," he said.

I guess the gloves are off?

In terms of motivations, it's not hard to guess why McCain is unloading on the former Massachusetts governor -- McCain has a lot of ground to make up, and Romney's record makes him vulnerable. Indeed, everything the Arizona senator said about Romney yesterday was true.

But I wonder if McCain underestimates his own vulnerabilities on this. If the race for the GOP nomination comes down to who is the most loyal partisan and fiercest advocate of the Republican agenda, McCain's going to lose.

I started thinking about the past few years, and McCain's record is ripe for the picking. He's worked with Sen. Russ Feingold (D-Wis.) on sweeping campaign-finance reform, former Sen. John Edwards (D-N.C.) on a Patients' Bill of Rights, and Sen. Ted Kennedy (D-Mass.) on immigration reform -- all bills the GOP opposed in large numbers. McCain voted against Bush's tax cuts in 2001 and 2003, and the anti-gay constitutional amendment last year. In March 2004, asked on national television whether he would consider joining the Democratic presidential ticket as John Kerry's running mate, McCain said, "John Kerry is a close friend of mine. We have been friends for years. Obviously I would entertain it."

A month later, in April 2004, just as the national Republican campaign was beginning in earnest, McCain said, "I believe my party has gone astray.... I think the Democratic Party is a fine party, and I have no problems with it, in their views and their philosophy."

And now McCain has decided his path to the nomination will be decided by a fight over who is the "real" Republican in the race? Is this really a wise strategy?