Really rich people aren't actually that good at buying their way into political office

Bruce Rauner is the first Republican governor of Illinois in more than a decade — but his victory didn't come cheap. As Nick Confessore details in the New York Times, Rauner, a wealthy financier, spent $27.5 million of his own money to get elected, and raised millions more from a few wealthy families. Now that he's in office, he's proposed sweeping tax cuts and restrictions on public unions — a surprisingly conservative agenda for such a blue state.

But when it comes to wealthy individuals who "self-fund" their campaigns for office, Rauner's success is very much the exception rather than the rule.

In fact, study after study has found that self-funders like Rauner have a really hard time winning — even if they spend truly massive sums (which, according to the Supreme Court, they have the right to do).

The failure of self-funders was particularly glaring in 2010, the year the infamous Citizens United decision. Out of the eight Senate and House candidates who spent the most of their own money on their campaigns in 2010, just one ended up winning. The losers — most of whom were unsuccessful Republicans in a year their party swept a majority of congressional races — included Linda McMahon, who spent $46 million running for Senate in Connecticut, and Carly Fiorina, who spent $5.5 million running for Senate in California. Most impressive of all was Meg Whitman's losing campaign for governor of California — she spent around $144 million of her own money and lost by 13 percentage points.

Their losses are nothing new. Political scientist Adam Brown found that self-funders in gubernatorial races had poor showings in a 2009 research presentation titled "What Money Can't Buy." And political scientist Jennifer Steen reviewed congressional self-funders in a 2006 book on self-financing and found that, amazingly enough, "a candidate's chance of winning a primary or general election tends to decrease as the amount of personal funds invested in their campaigns increases."

Traditional political fundraising is about more than just getting money

You might think self-funders' struggles are explained by inexperience. Many self-funders have little or no experience in elected office, so it makes sense to expect that they'd naturally have a hard time on the campaign trail and end up losing.

But for Steen's book Self-Financed Candidates in Congressional Elections, she separated out self-funders who did have political experience from those who didn't — and even once that was controlled for, ordinary fundraising was much more closely correlated with success than self-financing was.

Indeed, Steen wrote that her evidence suggests the marginal impact of "a dollar self-financed does not equal a dollar raised." That may seem weird, since these dollars tend to be spent on the same sorts of things.

But traditional political fundraising necessarily involves building a network of some sort. Whether it's big-dollar black-tie events or small online donations, the candidate has convinced actual people to fork over some of their hard-earned cash.

And, Steen argued, the effects from that network-building can ripple outward in several ways. The most obvious is that the donors themselves will presumably vote for the candidate they're giving to. Donations from groups, which usually come with endorsements, could bring in even more votes.

Beyond that, contributions can be a signal of a candidate's political strength to other political players like "potential opponents, opinion leaders, reporters, strategic campaign contributors," Steen wrote. If you raise a lot of money, you look like a winner whose candidacy is "catching on" among actual people.

But if you just spend your own money — well, any rich person can do that. Indeed, a candidate's very willingness to spend millions and millions of his or her own money might be compensating for an inability to build a network of supporters, or a lack of interest in doing that difficult work.

Campaign donations often follow political strength. Self-funding doesn't.

In addition to all this, there's a bit of a chicken-and-egg problem in disentangling how money's influence on elections actually works.

Ordinarily, it is true that the candidate who raises more money usually ends up winning. However, that candidate may have been able to raise that money because he or she was already believed to be likely to win. Nobody wants to waste money donating to a loser, after all. So outside fundraising often correlates with political strength — and can perhaps amplify it.

And in races with self-funders, there's another confounding factor — if they're facing a really tough race, they're likely to spend even more money on it. So when you eyeball the list of candidates who spent the most money on their own campaigns, they naturally tend to be embroiled in difficult races. "Self-financing may be as much a sign of weakness as a sign of strength," political science professor John Sides wrote in 2010.

Look at Linda McMahon of Connecticut, the top self-funding congressional candidate of the 2010 cycle. Connecticut is a blue state, and the Democratic nominee that year, then–Attorney General Richard Blumenthal, was generally considered to be a strong contender (though not perfect). So, trailing in polls and trying to make the race competitive, McMahon poured in millions. (She never got close, losing by 12 points in a Republican wave year. She ran for Senate again two years later and lost again, and spent $100 million in the two losing races combined.)

Conversely, if the self-funder were in a really strong political position, we might even expect him or her to spend less. Candidates certain to be elected may be happy to throw away their donors' money anyway — that's why the money was given in the first place, after all. But a self-funder may be more reluctant to part with his or her own cash unless it seems truly necessary.

Conditions were favorable for a Rauner victory

None of this is to say that self-financing is meaningless. It can certainly elevate a candidate from obscurity to the top tier. Steen found that in open primaries, if a self-funder enters the race, other potential opponents are often deterred from jumping in themselves. And of course, there have been some notable self-financed success stories — like former New Jersey Gov. Jon Corzine, former New York City Mayor Michael Bloomberg, and, of course, Bruce Rauner.

But even though a rich Republican like Rauner managed to win blue state Illinois, it's worth remembering a couple things. First, his opponent, incumbent governor, Pat Quinn, was one of the most unpopular governors in the country. And second, Rauner won in a nationwide GOP wave year in which Republicans also won governor's races in blue states like Maryland and Massachusetts — and he won by less than 4 percentage points.

It's certainly possible — even likely — that Rauner's massive spending helped him overcome his own weaknesses as a candidate. But it certainly didn't create the conditions for future Republican success in Illinois. So overall, while there are many, many ways in which money influences our politics, the track record of self-funders suggests this isn't a particularly effective one.

What does this mean for Donald Trump?

Surprisingly enough, all this may not actually have too many implications for this year's highest-profile "self-funder" — Donald Trump.

That's because despite his claims that he's financing his own campaign, Trump has actually relied quite a bit on what his campaign has called "unsolicited" donations.

According to the latest campaign finance filings, Trump had put a little less than $2 million into his campaign. But he raised twice that amount — $4 million — from others, particularly those buying his merchandise (like his "Make America Great Again" hat). The Sunlight Foundation's Drew Doggett has a good rundown of this here.

Trump constantly brags about his vast wealth, and has said he'd spend more than $100 million to win the GOP primary, if necessary. But considering how cheap he's been so far, there's a lot of skepticism about whether he actually will.

For instance, so far Jeb Bush's operation has spent over 100 times more on ads this year than Trump's operation has — $30 million to $217,000, according to NBC/SMG Delta.

Trump, of course, is leading the polls despite this lack of spending. So if he starts to lose his lead, maybe he'll spend big to try to take it back. But for now, we don't yet know whether he'll join the ranks of the historic self-funders like McMahon.