Huckabee is not without weaknesses as a potential running mate. The former governor might help McCain shore up the conservative and evangelical blocs, but Huckabee shares some of McCain’s troubles.

Like McCain, he has been targeted throughout the campaign by some Washington groups, particularly anti-tax groups such as the Club for Growth. Nor did members of the evangelical movement fall in line behind the former Baptist minister.

“It would be great if McCain chose a good fundraiser to balance out that weakness,” Republican strategist Karen Hanretty said.

Romney has also been floated as a possibility this week, but those floating it concede it is a “fantasy.”

Romney and McCain have shown deep disdain for one another, and what was a two-man race between them has been decidedly nasty.

Jim Pitts, a veteran Republican operative, pointed out that Ronald Reagan picked George H.W. Bush after a bitter primary battle in 1980.

“It was as tough if not tougher than this one,” Pitts said. “A lot of people said those two could never get together. The two campaigns didn’t like each other. Their people didn’t like each other.”

Most analysts think Romney and McCain are beyond reconciliation.

Florida Gov. Charlie Crist endorsed McCain late in the Sunshine State’s contest, and was largely credited with helping McCain get over the hump there.

Crist is said to be ambitious, and several sources have said he would be interested in the number-two spot if it were offered. As the popular governor of arguably the most important swing state in the country, his presence on the ticket has to be considered a big plus.

Minnesota Gov. Tim Pawlenty has done yeoman’s work for McCain throughout last year, even as McCain’s campaign was left for dead by the political class.

Despite Democratic wins in the state, it continues to be purple and the home of this summer’s Republican convention. Pawlenty would also offer youth; McCain turns 72 in August.

Former New York City Mayor Rudy Giuliani has proved he can raise money and draw a crowd. He was quick to endorse McCain after a poor showing in Florida, and he still has credibility on terrorism issues.

Sen. Kay Bailey Hutchison (R-Texas) was floated by some analysts, particularly if another woman senator was on the other ticket. Former Homeland Security Director and ex-Pennsylvania Gov. Tom Ridge has also campaigned hard for McCain.

Bruce Oppenheimer, a political science professor at Vanderbilt University, said it is a mistake to think running mates in the modern era are chosen for strategic reasons over personal reasons.

Oppenheimer and others suggested that the last time a running mate was chosen successfully for regional, strategic purposes was in 1960 when John F. Kennedy tapped Lyndon B. Johnson of Texas.

In the modern era, Oppenheimer said, it might be just as important to a nominee that he or she not be upstaged.

“In the end, it’s up to the nominee,” he said.