Lately, Mitt Romney has been so consumed with fundraising that his aides have had to defend his absence from the stump. Like his foe, the Republican nominee is in the midst of a frenzied financial arms race. But one hugely wealthy individual has not yet been persuaded to part with much cash to support the Republican cause: Mitt Romney himself.

Mitt Romney is hardly the first wealthy individual to seek the White House. John F. Kennedy once quipped he had received a telegram from his father: “Don’t buy another vote. I won’t pay for a landslide.” But Romney, for whatever reason, has failed to use his personal wealth to pay his campaign’s bills. His refusal to self-finance is one of the mysteries of this campaign.

After all, if Romney were to help fund his own bid, he would have ample company. In 1976, the U.S. Supreme Court ruled that it would violate the First Amendment to limit what candidates can spend on their own behalf. Ever since, wealthy office-seekers commonly have ponied up. John Kerry lent more than $6 million to fund his Iowa caucus drive in 2003. Hillary Clinton lent her campaign over $11 million four years later. Steve Forbes gave his 1996 campaign $32 million, and spent nearly $37 million four years after that. Ross Perot spent $63 million to finish strongly in 1992, back when that was real money.

In fact, four years ago the former governor gave his own campaign nearly $45 million. He even donated a Winnebago trailer. “I’m not beholden to any particular group for getting me into this race or for getting me elected,” ABC News quoted him as saying. “My family, that’s the only one I’m really beholden to — they’re the ones who let their inheritance slip away, dollar by dollar.”

The Romney boys can sleep easy: Their dad’s assets are worth nearly $250 million, according to financial disclosure forms. But he has put only $150,000 into this year’s run, through a joint gift with his wife Ann to a Republican committee last spring.

Romney’s campaign surely could use the money. His summer fundraising was less robust than it appeared, since much of it was committed to party committees not controlled by him. His campaign borrowed $20 million as a “bridge” loan to keep ads on the air before the general election began. Even the super PACs have less on hand now than seemed likely just a few months ago. His strategist Ed Gillespie bemoaned the time Romney must spend fundraising. “I don’t think anybody considers Utah to be on the target state list, but it was an important event for us,” he said of a recent fundraiser held in Salt Lake City, according to BuzzFeed.

So why Romney’s reticence? Maybe this is a classic “dog that didn’t bark,” where inaction tells us more about the candidate than he wants us to know.

It could be that the candidate is, as advertised, cheap. Recall that when his friends tried to “humanize” him at the Republican Convention, they reminisced that he invested in Staples because “he really got excited at the idea of saving a few cents on paper clips.” No doubt he finds such spending distasteful. He once bragged he had forced Senator Edward Kennedy to mortgage his home to hang on to his seat. For his part, he has fretted publicly that spending his own funds would be “akin to a nightmare.” Perhaps self-financing would violate his sense of privacy and self-reliance.

Also, his money may not be easy to access. We know that much of it is tied up in offshore accounts and complex tax-driven trusts. It seems unlikely that he could walk up to an ATM and walk away with $50 million in $20 bills.

Or perhaps he has made a political calculation. A large gift could open him to the charge he is trying to buy the presidency. That seems unlikely, though. Voters rarely hold such self-largess against politicians; just ask Mayor Michael Bloomberg.

There may be a simpler, but more troubling, explanation. Romney may find himself just as confused, and perhaps as mortified, by the new campaign finance system as the rest of us. Thanks to the U.S. Supreme Court’s 2010 Citizens United ruling and other lower court decisions, individuals and corporations can give unlimited sums to super PACs so long as they pretend not to coordinate with candidates. Meanwhile, donors can give unlimited secret funds to shadowy 501(c)(4) organizations, such as the one wielded by Karl Rove. Billionaires such as Sheldon Adelson now sponsor candidates as if they were racehorses. Mitt Romney might find himself just as surprised as anyone at how his own campaign seems less flush than it seemed just a few weeks ago, with initiative and power flowing to the purportedly independent groups that now constitute a de facto Republican Party. In this dystopian landscape of campaign finance, maybe Romney just counted wrong.

To be clear, pity is not in order. Romney and the Republicans have plenty of money. But his reluctance must rankle some donors who are being asked to give substantial sums. As the campaign lunges toward the finish, more Republicans may start to ask how committed he is to winning the race if he won’t put his own money on the line.

PHOTO: Republican presidential candidate and former Massachusetts Governor Mitt Romney speaks at the Clinton Global Initiative in New York, September 25, 2012. REUTERS/Brian Snyder