What would it take to make the White House wannabes stop chasing after big donors? From 1975 to 1999, the answer was federal matching funds — money that candidates could get by raising more money from small donors and spending less time schmoozing with the well-heeled.

Now, the U.S. PIRG (Public Interest Research Group) Education Fund, an advocate of more limits on campaign money, has produced a model of how that would affect the early stages of the 2016 race. The analysis assumes a 6-to-1 match, so the match would turn a $200 contribution into $1,400 for the candidate.

First the results, then the caveats.

The results:

  • The big winner — Sen. Bernie Sanders. In the first half of 2015, he got 77 percent of his money in small contributions, that is, $200 or less. Hillary Clinton raised about 3 1/2 times as much as Sanders, but just 13 percent came from small contributions. With matching funds, Sanders would end up with $83 million, Clinton with $89 million.
  • The big loser — Republican Jeb Bush. He would be the only contender to come out with less money. It reflects the top-heavy profile of Bush's fundraising: 88 percent of his money came from donors who gave $2,700, the legal limit. Republicans who would benefit most are Sen. Ted Cruz and retired neurosurgeon Ben Carson.

The caveats: Intriguing as this might be, the analysis is far from ironclad.

SuperPACs: For one thing, it doesn't take into consideration superPACs. Every major candidate but Sanders has at least one backing them (that they endorse). SuperPACs have no contribution limits.

A theoretical system with matching funds could also theoretically ban superPACs. But here in 2015, Bush raised $11 million for his campaign committee, and $103 million was raised for the superPAC. In most of the presidential campaigns, the small donors to the candidate's committee look a lot like window dressing.

There are cost-benefit questions: For the 12 candidates, who have reported their fundraising so far, the analysis estimates that $307 million in matching funds would have displaced $65 million in contributions greater than $200. Advocates of public financing say no one can gauge the true benefit: how many federal dollars would be saved if big donors had less sway over lawmakers.

Public financing is a long, long way from reality: The Watergate-era system was abandoned twice, first by candidate George W. Bush in the 2000 primaries, and then by candidate Barack Obama in the 2008 general-election campaign. It's not going to be resurrected — at least not in the short term.

Matching funds programs are included in comprehensive campaign-finance bills proposed by Rep. John Sarbanes, D-Md., and Sen. Dick Durbin, D-Ill. They're better designed than the old presidential system. But unlike the 1970s — or even 2002, when the McCain-Feingold bill became law — campaign finance has become a partisan issue. The epithet "welfare for politicians" likely still has some punch.

Copyright 2016 NPR. To see more, visit http://www.npr.org/.