Commenting on the political landscape, now six years after the U.S. Supreme Court's Citizens United ruling, former U.S. President Jimmy Carter laments that Washington D.C. has become corrupted by the influence of money.

"We've become, now, an oligarchy instead of a democracy," Carter told Oprah Winfrey in an interview excerpt released on Tuesday. "I think that's been the worst damage to the basic moral and ethical standards to the American political system that I've ever seen in my life."

When asked if he would be able to become president today, the Nobel Peace Prize winner answered: "Absolutely not."

"There's no way now for you to get a Democratic or Republican nomination without being able to raise $200 or $300 million, or more," Carter continued. "I would not be inclined to do that, and I would not be capable of doing it," he added.

The current presidential campaign has seen an unprecedented amount of money flow into both the candidates' own coffers as well as into the super PACs that support them.

What's more, this tidal wave of cash is coming from a handful of the nation's wealthiest donors. Reportedly half of the $388 million contributed so far to campaigns on both sides of the political spectrum came from fewer than 400 families, with 62 donors giving at least $1 million.

Carter's interview, which will be aired on Sept. 27 on Oprah's SuperSoul Sunday program, was reportedly taped just before the the 91-year-old announced last month that he would be undergoing treatment for stage 4 melanoma.