As their uncomfortable joint appearance Wednesday in New Hampshire made clear, 2008 GOP rivals Mitt Romney and John McCain really don't like each other. With good reason. Four years ago, Romney suggested McCain's out-of-control temper made him unfit while the Arizona Senator called the Massachusetts Governor an "a$$hole" and a "f!@#%ng phony" in private. But on Valentine's Day 2008, Romney swallowed his pride and endorsed McCain for President, a grudging favor returned yesterday. As it turns out, that's not all Romney swallowed. To get a crack at the VP slot on McCain's ticket, Mitt Romney ate the $45 million he had loaned his own campaign.
As the Boston Globe reported on July 16, 2008, Romney "will not seek donations to repay $45 million in personal loans he made to his failed presidential bid -- the biggest ever made by a candidate in a primary campaign." The Globe explained the importance of that write-off for the $250 million man who this year declared himself part of the "80 to 90 percent of us" who are middle class.

The move could clear away the last remnants of a divisive primary race, insuring that he and his financial supporters are focused on helping McCain...Still, Romney's investment in his own campaign and the donor network he built may have helped his vice presidential stock go up. The $45 million helped win widespread name recognition for Romney, who also raised more than $65 million from donors. Since McCain clinched the nomination in March, Romney has asked his supporters to contribute to a Republican National Committee fund that will be used to help McCain's candidacy and he has urged his campaign finance team to work for McCain.

As Politico detailed two weeks earlier, those deep pockets made Mitt an attractive choice as McCain's running mate, provided they weren't being emptied to pay himself back:

In a surprise to many Republican insiders, former Massachusetts Gov. Mitt Romney is at the top of the vice presidential prospect list for John McCain...
One of the chief reasons the Massachusetts governor is looking so attractive is his ability to raise huge amounts of money quickly through his former business partners and from fellow members of The Church of Jesus Christ of Latter-Day Saints, the Mormons.
McCain sources tell Politico that they believe Romney could raise $50 million in 60 days. One close Romney adviser said it could even be $60 million.

Ultimately, of course, the two men's "lack of personal chemistry" and McCain's reckless gamble in choosing Sarah Palin undermined Romney's multi-million dollar investment. Nevertheless, Romney dutifully raised money for McCain and served as his attack dog at dozens of events around the nation. In April 2008, Romney blasted Barack Obama for "the kind of elitist view of America that has long characterized those of the most liberal persuasion in our country." That August, Romney announced that John McCain had "earned" his too-many-to-remember houses with his "hard work," while playing the false Rezko card against Barack Obama. Romney then upped the ante, suggesting that McCain's multiple mansions were reasonable compensation for "being homeless for five years."
And to be sure, Mitt Romney knows a thing or three about mansions. In the past year, Romney sold two of his four multimillion dollar mansions because he and his wife were, according to an aide, "downsizing and simplifying." In addition to his Boston area townhouse, Mitt owns a lakeside mansion with man-made beach in New Hampshire and $12 million, soon-to-be doubled-in-size California beach side home.
Romney could have bought four more, if not the number two spot on the McCain ticket, with the $45 million he wrote off in 2008. Still, four years after he endorsed the man who called him a "f!@#%ng phony," Mitt Romney finally got a pay-off from his investment in John McCain.