If you’ve got money to burn, get into politics—as a donor giving millions to the big-money groups known as super PACs.

Rich donors have transformed politics since the 2010 Citizens United Supreme Court decision cleared the way for unlimited spending on behalf of favored candidates. Super PACs spent $609 million in the 2012 presidential election, with even greater spending expected in 2016. Most candidates feel it’s essential to woo 1 percenters and spend considerable time persuading them to give big.

But a fat bank account doesn’t automatically buy victory, a lesson being hammered into wealthy donors this year. Wisconsin Gov. Scott Walker was one early favorite of big donors—especially Wall Streeters—yet he flamed out last August months before voting ever began. Jeb Bush raised more super PAC money than anyone, yet he quit in February without winning a single primary. Many rich donors then turned to Marco Rubio, who won just one state—Minnesota—before he bailed out on March 15.

Here’s a breakdown of spending for all the major candidates who have left the race:

Source: Federal Election Commission More

All told, GOP donors have spent more than $200 million on super PACs supporting candidates who are out of the race. That money bought essentially nothing. Most donors realize they’re gambling with their money, since there can only be one winner in a presidential race and most candidates are destined to lose. But the popularity of Donald Trump and Bernie Sanders—who have both eschewed super PACs—shows that ordinary voters still matter, at least a little.

Trump’s renegade candidacy is obviously one reason millions of dollars in donor funds aren’t buying success this year. Trump may get more free media exposure than any presidential candidate in history, thanks to the controversy he stokes and entertainment value he provides on radio and TV. He’s also adept at using social media—which is free—to circulate his views and attack his foes.

Yet the return on investment for big donors is generally weak, and far below what many of them would tolerate in the businesses or other ventures they typically run.

A 2015 Yahoo Finance investigation, for instance, found that rich donors often back losing candidates because they line up behind ideologues they find common cause with, rather than more moderate politicians who appeal to a broader range of voters. There may also be diminishing returns on political ads, one of the main things super PACs finance. Ads tend to clog the airwaves in swing states that determine elections, and there’s probably a saturation point at which voters simply tune out ads and other information about candidates.

While much of the Wall Street and other big money has been neutralized in the 2016 race, some of it could still prove decisive. Hillary Clinton’s primary super PAC has raised more than $51 million and is still sitting on most of it, which could give her a head start in the general election, since she seems well on her way to clinching the nomination and may not have to spend much more in the primaries. And she’s certain to raise a lot more. Ted Cruz has four super PACs that have raised about $41 million and spent only around $17 million. John Kasich’s super PAC has raised far less, but more contributors might step up now that he won the Ohio primary.

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