Former President Jimmy Carter said this week that he considers the United States an "oligarchy" where "unlimited political bribery" has resulted in "a complete subversion of our political system as a payoff to major contributors."

Responding to a question about the 2010 Supreme Court decision on Citizens United involving campaign financing, 90-year-old Carter said on the "Thom Hartmann Program" radio show that both Republicans and Democrats "look upon this unlimited money as a great benefit to themselves."

"Our Supreme Court has now said, 'unlimited money in politics,'" host Thom Hartmann said. "It seems like a violation of principles of democracy. ... Your thoughts on that?"

"It violates the essence of what made America a great country in its political system," Carter responded. "Now it's just an oligarchy, with unlimited political bribery being the essence of getting the nominations for president or to elect the president."

Oligarchy is defined by Webster as "a government in which a small group exercises control especially for corrupt and selfish purposes."

The Citizens United ruling lifted restrictions on political spending by corporations and unions and dramatically altered the landscape for campaigns by allowing for the creation of super PACs that can accept unlimited contributions from donors and spend that money on electing or defeating political candidates.

Carter continued: "And the same thing applies to governors and U.S. senators and congress members. So now we've just seen a complete subversion of our political system as a payoff to major contributors, who want and expect and sometimes get favors for themselves after the election's over. ... The incumbents, Democrats and Republicans, look upon this unlimited money as a great benefit to themselves. Somebody who's already in Congress has a lot more to sell to an avid contributor than somebody who's just a challenger."

A recent study from Princeton University and Northwestern University supports Carter's claim, concluding that America is more akin to an oligarchy than a democracy.

"Despite the seemingly strong empirical support in previous studies for theories of majoritarian democracy, our analyses suggest that majorities of the American public actually have little influence over the policies our government adopts," the study authors wrote. "Multivariate analysis indicates that economic elites and organized groups representing business interests have substantial independent impacts on U.S. government policy, while average citizens and mass-based interest groups have little or no independent influence."

Supreme Court Justice Ruth Bader Ginsburg also spoke out against Citizens United this week, saying Wednesday that the ruling was the "most disappointing" decision in her 22-year tenure, as HNGN reported.

Listen to a portion of the Carter interview below.