David Trone (Marlon Correa/El Tiempo Latino)

Update: Trone lost to state Sen. Jamie Raskin on Tuesday, 34-27, becoming the latest massive self-funder to come up short. Kathleen Matthews finished third.

We live in an era in which one unlimited bank account can fundamentally shift the dynamics of a political race.

Usually the big, course-altering bucks come in general election or presidential races. And usually they're from outside groups, since there's no rule about how much billionaires and their affiliated groups can spend on a race. Think Sheldon Adelson almost single-handedly keeping Newt Gingrich afloat in the 2012 GOP presidential primary.

But there's also no rule about how much a candidate can spend on his or her race. And every once in awhile, we get a candidate willing to invest eye-popping sums to help elect themselves to public office. It certainly helps raise their profiles, but there's little evidence to suggest it helps them win elections.

Enter David Trone, a wine magnate with shops in 21 states. The first-time congressional candidate has spent $12.4 million of his own money to try to win Tuesday's nine-person Democratic primary for an open congressional seat in Maryland.

That's a huge, almost unheard-of sum for a primary. No other House candidate has spent more than $10 million of his or her own money, and very few have even come close. Trone's spending, in fact, averages out to $49.55 per registered Democratic voter in the suburban Washington, D.C., district he's trying to represent, according to 2014 voter data.

Put that in even more context: So far in the presidential race, GOP front-runner Donald Trump has loaned or spent less than three times that amount — $36.2 million — of his own money trying to become the GOP presidential nominee.

Trone's investment alone would make the Democratic primary in Maryland's 8th Congressional District the second-most expensive general election House race in 2014 (outside group spending excluded), according to a tabulation from the Center for Responsive Politics. It puts him in the exclusive group — albeit at the bottom — of the 28 or so presidential, gubernatorial and congressional candidates who have spent $10 million or more of their own money on their campaigns. Trone is one of only two House candidates on this list, along with Phil Maloof, who lost a New Mexico House race in 1998.

(Philip Bump / The Washington Post)

Trone says the investment was necessary to get his name out there. He's up against better-known candidates like Kathleen Matthews — wife of MSNBC "Hardball" host Chris Matthews — and state Sen. Jamie Raskin.

Trone's name recognition has come almost entirely from how much money he's spent in this race — first by the sheer number of ads introducing himself to voters in D.C.'s expensive media market, and second by the simple fact that he's spent a ton of money. (His net worth is somewhere between $17 million and $68.5 million, so it's hard to say what percentage of his own wealth Trone put into this.)

The 2010 Citizens United decision opening up unlimited amounts of money in politics has created this alternate political universe where being rich is more than just a financial advantage; it can also be a political advantage. Millionaires and billionaires can point to their flush bank accounts and argue that they're not beholden to anyone, an especially potent thing to say in a year when outsiders seem to be more desirable than ever.

It's one of Donald Trump's main selling points. It's been Trone's, too. His website blocks donations of more than $10, notes NPR's Jessica Taylor.

But throwing a stunning amount of money into a political race is not without risk. His opponents point out that, before this race, Trone was one of those wealthy donors he's now eschewing.

And for whatever reason, self-funders' track records aren't that great. The Center for Responsive Politics' Will Tucker notes that of the 500-plus candidates who have provided more than half of their campaigns' funds since 2010, just 11 won. That's a 2 percent win rate.

So if Trone wins the primary Tuesday, he'll not only be among a small group of candidates who have spent $10 million or more on their campaigns, he'll also be among an even smaller group of candidates whose investments have actually paid off.

Assuming a congressional seat is actually worth $12 million, that is.

The Fix's Philip Bump contributed to this report, mostly by checking my math and making that cool graph.