Former presidents Bill Clinton, left, and Jimmy Carter shake hands after Carter spoke at a Clinton Global Initiative meeting on Tuesday in Atlanta. (John Bazemore/AP)

Former president Jimmy Carter, who won election in 1976 largely because of public financing, says it is time to move back to a system in which campaigns rely on taxpayer money to pay for general elections.

In an interview with fellow former Oval Office holder Bill Clinton, Carter said the system encourages public participation in the electoral process. “Personally, I'd like to see public funds used for all elections — Congress, U.S. Senate, governor and president," Carter said at the Atlanta meeting of the Clinton Global Initiative.

Clinton, whose wife, Hillary, is the presumptive Democratic Party nominee in what is expected to be the most expensive presidential election in U.S. history, did not respond to Carter’s idea.

Carter first criticized the Supreme Court’s "stupid Citizens United decision," which opened the floodgates for unlimited contributions in the presidential race. Bu,t he said, "another thing we could do is go back to presidential campaigns just using public funds for the general election," like the system that allowed him to effectively compete against incumbent Republican President Gerald R. Ford.

Carter, when he ran for the presidency, was a relatively unknown Georgia governor, but he and Ford both received $20 million in 1976 from the Presidential Election Campaign Fund, a post-Watergate reform funded by a $3 option on individual income-tax returns. The fund is supposed to level the playing field in presidential elections. To receive public money, candidates must agree not to accept private contributions.

More than $300 million now sits unused in the fund because most candidates no longer want to agree to its spending and fundraising restrictions. So far, the only major-party candidate to have sought public money in the 2016 primary was Democrat Martin O’Malley, the former Maryland governor.

Rep. David E. Price (D-N.C.) sponsored a bill to reform the system to bring it in line with modern election costs, but the measure has fierce Republican opposition.