That scenario played out in May when Simmons, at one time considered the favorite to win the GOP nomination in the Connecticut Senate race, suspended his campaign, citing "the mathematical reality of competing against an opponent with unlimited financial resources." Simmons re-entered the campaign in late July.
Other top self-funders include billionaire real-estate investor Jeff Greene, who has forked over $5.8 million to win the Democratic nomination for the open Senate seat in Florida; hospital entrepreneur Rick Scott, who has spent $22 million to win the GOP nod in the same race; and former E-Bay executive Meg Whitman, who Hewlett Packard CEO Carly Fiorina, a Republican who has sunk $5.5 million into her bid to unseat Democratic Senator Barbara Boxer.
Former eBay chief executive Meg Whitman has dropped $91 million of her own cash into her run as a Republican candidate for governor in California, poising her campaign to become the largest self-financed bid of the season.
Of course, spending tens of millions of dollars of your own cash to run for office does not guarantee a win.
Historically, self-financed candidates have a lower rate of winning elections than traditional candidates. Dave Levinthal, communications director of the Center for Responsive Politics, said McMahon's victory Tuesday makes her "an exception to the overriding, but little-known rule of politics: that self-financed candidates typically lose."
One study by the non-profit National Institute on Money in State Politics found that in the last nine years, only 11 percent of the self-financed candidates who have run for state and federal office have made it into office. While polls have shown Greene and Scott leading their respective races in Florida, some polls have shown those leads narrowing recently. Last week, Republican George Flinn dropped $2.9 million on a U.S. House primary in Tennessee and lost badly.
A strong anti-incumbent wave this fall could help some of this year's batch of self-financers buck that poor track record and motivate both political parties to step up their efforts to seek out more wealthy candidates for future cases. "This current election cycle could … prove somewhat different," said Levinthal, because several of the wealthy candidates are running strong campaigns. He cited McMahon, Greene, Fiorina and Whitman. The potential for a successful self-funding boomlet concerns campaign finance watchdogs.
"We run the risk of having a body that looks less and less like America," said Sheila Krumholz, executive director of CRP.