Is “Flip,” the flip-flop-baiting, Mitt Romney-hating dolphin that follows the former governor of Massachusetts around, going to have to start tailing Mayor Giuliani?

While the former New York City mayor and Republican frontrunner doesn’t yet have the Utah-size flip-flopping problem of Mr. Romney, he has announced his change of mind this week on a second major issue of concern to Republican primary voters: campaign finance regulation.

Asked at an event in Iowa on Monday whether he would roll back the 2002 McCain-Feingold campaign finance law, Mr. Giuliani expressed his admiration for Senator McCain but then gave his first definitive statement of the primary campaign that he would be abandoning his prior support for the Arizona senator’s signature law.

“I supported McCain-Feingold. … The concept made sense to me,” Mr. Giuliani began, in a response his campaign sent to the press yesterday. But then he added: “Now that I see it play out in a couple of elections, I think it was a mistake. We should get much closer to being able to allow people to — to realize their rights of free speech in the way in which they get involved in campaigns, make contributions to campaigns.”

Conservatives, of course, will be happy with this change of position on Mr. Giuliani’s part; they’ve long seen McCain-Feingold as little more than an attempt to shut up right-wing interest groups.

But at what point does the former mayor risk veering into flip-flopper territory? I mentioned that campaign finance represented Mr. Giuliani’s second shift on a major issue of concern to Republican voters. The first came in late April, when Mr. Giuliani reversed his long-standing support of civil unions and came out in opposition to the civil union law New Hampshire was in the process of passing.

Both of these shifts have been from somewhat liberal positions to positions more in tune with the Republican base. Yet Mr. Giuliani so far seems rather immune to the flip-flopping tag that has bedeviled Mr. Romney with the Republican base and Mr. McCain with his former fans in the press.

A number of factors seem to be in play.

Number: If Mr. Giuliani is making a few concessions to political reality, Mr. Romney is a virtual concessions stand. The list of Mr. Romney’s flips and flops would take up more words than they’re worth, but just to give it a go: abortion (arguably, more than once), stem-cell research, gay rights, immigration, gun control, taxes, whether he’s ever been hunting, and, yes, campaign finance legislation. Mr. Romney’s rivals would have to put on quite a show to compete.

Size: Mr. McCain used to enjoy a halo from the press and a loyal base of independents. He could simply do no wrong. However, having once stood as a foil to the evil Bush regime, Mr. McCain decided to ditch his Mr. Maverick image for what he thought would be an advantageous upgrade: Mr. Establishment (aka Bush’s Best Buddy). But when the Mr. Establishment image and closeness to President Bush didn’t make him the invincible frontrunner of the Republican primary as he had expected it to, he was left a man without an identity. While Mr. McCain has done little flip-flopping on individual issues (Mr. Bush’s tax cuts, creationism in public schools), his flip-flopping on his very identity has left him gravely damaged — probably irreparably so.

Weight: Lastly, there’s the weight of all the flips and flops the candidates have executed. Mr. Romney has changed positions on what Republican voters see as core issues. What kind of man can he be, really, if all of his beliefs are up for grabs? Meanwhile, Mr. Giuliani may have shifted some, but he remains at odds with huge segments of the Republican base on key issues. Most important (and obviously), he’s barely budged on abortion. And while he’s made some noises about respecting the Second Amendment, he hasn’t apologized for any of the gun restrictions he pushed as mayor.

Ultimately, it seems that stubbornness in opposition to the base is more appealing to voters than pandering to it. That doesn’t mean a candidate should be intransigent about all of his or her beliefs (see: Mr. McCain’s experience with immigration reform). But it does mean candidates have to pick wisely where they bend and where they remain rigid.

So far, Mr. Giuliani’s choices have kept Flip at bay.