Money can buy ultra-rich donors many things in American politics - influence, proximity to power, the ability to assist their favored political party or pet issue.
But it doesn't always buy them victory.
In 2012, conservative casino mogul Sheldon Adelson contributed a whopping $93 million to outside groups helping Newt Gingrich (in the primaries) and Mitt Romney (in the general election). Both candidates lost.
Former New York City Mayor Michael Bloomberg has spent millions of dollars to push gun-control measures. Yet federal background checks for firearm purchases can't even pass the Democratic-controlled U.S. Senate.
And liberal billionaire Tom Steyer has lobbied the Obama administration to nix the Keystone XL Pipeline - whose fate remains uncertain.
"In any campaign, money is a key to victory, but not the key," said a longtime Republican operative who has worked closely with outside political groups. "Everything else equal, you want more of it. But a good opponent can balance it out through advantages in other areas."
After the proliferation of Super PACs and other outside groups, and after a Supreme Court ruling allowing Americans to donate to an unlimited number of campaigns and political parties, the focus has sharpened onthe super-rich who are flexing their political muscles more than at any other time in decades.
One reason money isn't everythingis that candidates and campaigns still matter.
In 2012, for instance, billionaires like Adelson and Charles and David Koch contributed millions of dollars to defeat President Barack Obama. But their preferred candidate, Mitt Romney, lost.
"Democrats benefited from the fact that the Koch Brothers and Sheldon Adelson have been so ineffective in spending their money," said Democratic strategist Bill Burton, who helped run the Super PAC backing Obama in 2012 (and financed largely by wealthy Democrats). "They had a historically bad candidate last time around."
Elections, said former Sen. John Sununu, R-N.H., ultimately come down to substance and reaching voters - often in ways other than 30-second television ads. "That money is somehow decisive is not only wrong," Sununu said on NBC's "Meet the Press" last Sunday, "it's probably going to be more wrong over time"as media and technology evolves.
"It's how you reach [voters]," Sununu added.
Money still provides an edge
Still, money remains a key ingredient when it comes to winning in American politics - money pays for the TV ads, the campaign headquarters, and the get-out-the-vote operations.
Indeed, on average, a better-financed campaign typically prevails over a lesser-financed one. According to one study, the side that had more money won 91 percent of congressional races in 2012. (Yet that statistic also says as much about the power of incumbency in congressional elections, since the incumbent tends to have more money than the challenger.)
"Money doesn't guarantee that you win elections, but it's certainly a huge advantage," says Fred Wertheimer, president of Democracy 21, an organization that champions campaign-finance reform.
Money also helps keep a candidate in the race.
In the 2012 primaries, Adelson funded a Super PAC that helped Newt Gingrich stay afloat after his disappointing fourth-place finish in Iowa caucuses. That Super PAC began airing TV ads hitting front-runner Mitt Romney, which contributed to Gingrich's victory (and Romney's loss) in the South Carolina primary.
Closing the cash gap
Money becomes less of an advantage when the lesser-financed side can at least close the money gap.
In 2012, all the organizations supporting Mitt Romney - including his campaign, the Republican National Committee, conservative Super PACs, and other outside groups - spent $583 million on TV ads, versus the $401 million that the Obama campaign and its outside groups spent, according to NBC's ad-tracking data.
Yet when outside groups were removed from the equation, the Obama campaign outspent the Romney campaign, $336 million to $213 million.
"In the end, the money variable in 2012 was more or less even between the two teams," said the GOP operative who has worked closely with outside groups. "Obama's campaign crushed Romney's campaign in resources."
The operative added, "But in the aggregate, [they] were roughly even because of the conservative outside groups."
NBC's Carrie Dann contributed to this article.