Rudy Giuliani’s endorsement of Mitt Romney breathtaking because of past - and present

During the 2008 Republican presidential campaign, John McCain delivered the coup de grace to Mitt Romney with victories in Florida and the Super Tuesday states, as well as a pair of gut-wrenching endorsements by then-Florida Governor Charlie Crist and former rival Rudy Giuliani.

Crist’s came after he initially pledged to stay neutral in the race but then backtracked three days before the Jan. 29, 2008, primary.

Giuliani, who banked on a Florida win to launch his candidacy, lost and instead came into the McCain fold in dramatic fashion on Jan. 30, 2008.

Just two hours before the final pre-Super Tuesday debate, he walked with McCain into a media filing center at the Ronald Reagan Presidential Library in Simi Valley, Calif., to announce he was ending his candidacy and backing the Arizona senator.

The former New York mayor, who had witnessed the horrors of the 9/11 terrorist attack firsthand, said he had settled on McCain because of the former Navy man’s national security credentials.

“Most importantly, my country will have a candidate for president of the United States where I can rest very assured - for myself, for my children, and for all the people we care about so much - that this is a man prepared to be president of the United States at a time of great peril,” Giuliani said.

Four years later, he has switched opinions and believes that Romney is the most capable candidate to lead the GOP against not just President Obama, but all foes foreign and domestic.

On Monday, Giuliani announced his endorsement of the former Massachusetts governor, their party’s presumptive 2012 nominee.

Such political endorsements between former rivals are commonplace. Romney ended up quitting the 2008 race and endorsing McCain himself little more than a week after Giuliani.

And McCain has returned the favor this time out, endorsing Romney immediately after what turned out to be an Iowa caucus loss and as the campaign returned to New Hampshire, a state where McCain had won the primary during the 2000 and 2008 campaigns.

“When I look at where we are as a nation and the challenges we face, I am convinced that Mitt Romney will provide a clear contrast to President Obama,” Giuliani said in a statement issued by the Romney campaign on Monday, as his home state of New York readied to hold its primary today.

“Whether it was creating jobs in business, rescuing the Olympics, or turning around Massachusetts’ $3 billion budget deficit, he has proved - time and again - that he excels at turning around difficult situations,” the former mayor said.

Giuliani’s comments today can’t simply be judged in the context of what he said four years ago. Time and circumstances change, of course, and Romney has to be compared to the candidates running now, not then.

But those past statement also can’t be ignored, given the additional context of the pointed criticism Giuliani leveled at Romney as recently as February.

At the time, the former mayor wasn’t a candidate in the heat of battle, struggling to differentiate himself from the rest of the field.

Instead, he had dispassionate distance, an outsider with no personal stake in the outcome.

In that context, he again decided against endorsing Romney. Instead, he favored former House Speaker Newt Gingrich, and used brashly New York language to explain his reasoning.

Giuliani homed in on a likely Democratic line of attack: that Romney is a chronic flip-flopper.

“There’s something wrong when you’ve been running as long as Mitt has and you’re at 25 percent (support),” he said Dec. 15 on MSNBC’s “Morning Joe.” “I think it’s deeper than just he’s kind of staid. I ran against him in ‘07, ‘08. I have never seen a guy ... change his positions on so many things so fast, on a dime.”

Giuliani added: “Now what will Barack Obama do to that? What Barack Obama will do to that is, ‘This is a man without a core. This is a man without a substance. This is a man who will say anything to become president of the United States.’ I think that is a great vulnerability.”

During a Feb. 5 interview, Giuliani didn’t back off, even as Gingrich faced increasingly long odds and Romney’s chances of winning the nomination increased.

“He has changed his position on virtually everything,” the former mayor said on the CBS News program “Face the Nation.”

Now Giuliani has done his own turnabout. Fast. On a dime.

For his part, Romney apparently has decided that consolidating his base is better than settling old scores.

Instead, he chose Monday to look forward, taking any mileage he can get from Giuliani’s backing as he attempts to unite his party for the campaign against Obama and the Democrats.

“I’m very proud to earn the support of such a distinguished leader and public servant to our country,” Romney said in the statement. “Rudy’s successes in turning around New York City are well-known and his name is synonymous with leadership, uniting a city in the aftermath of the worst terrorist attack in our nation’s history. I look forward to his help in the months ahead as I work to restore America’s promise and reverse President Obama’s failed policies.”

Glen Johnson can be reached at johnson@globe.com. Follow him on Twitter @globeglen.