Jimmy Carter
Jimmy Carter raised no money in his two presidential races because he relied on public funds.Getty

If he could do it all over again, and he was a younger man, Jimmy Carter still wouldn't run to become US president today. He couldn't afford to, he told reporters.

"I couldn't possibly do it because I have very little money," Carter said at a Pennsylvania press conference. "Now it takes $200m if you want any chance to get the Democratic or Republican nomination."

Carter , now 90, said he raised absolutely no money for his runs against Gerald Ford and Ronald Reagan because he relied on public financing of campaigns, reports the Times-Tribune. Barack Obama was the first president not to accept public funds in 2008 because he could raise more.

"Zero," Carter said. "And President Ford raised zero. And four years later when I ran against Ronald Reagan, zero. We didn't raise any money. So we weren't obligated to any special interest groups, and now, of course, very wealthy people are giving unlimited amounts of money, almost, because of the Supreme Court ruling on Citizens United," the Democrat added.

Carter was elected in 1976 when the campaign contribution landscape was radically different. Donations were far more limited before a series of Supreme Court decisions, most notably the Citizens United ruling, threw open the door to mega contributions like those by the billionaire Koch brothers. Now donors can essentially contribute as much as they want to as many candidates as they want. The court ruled that corporations and nonprofit organizations have the right to make unlimited independent political contributions, which the justices determined were protected by the First Amendment as a form of free speech. Unlimited individual contributions can now be veiled within Super PACs (Political Action Committees).

Carter has remained outspoken and active in international politics in an unofficial capacity. He's travelling to Gaza this week. But Israeli Prime Minister Benjamin Netanyahu and President Reuven Revlin flatly turned down Carter's invitation to meet. He has long been critical of Israeli policies toward the Palestinians.