WATCH: Bernie Sanders Rips Trump and Bloomberg, 'U.S. Democracy Becoming an Oligarchy'

MARTHA RADDATZ, ABC NEWS: What do you think about the possibility of former NYC Mayor Michael Bloomberg getting in the race? Another billionaire.

SEN. BERNIE SANDERS: Well, you know, I think it would be very interesting if Donald Trump became the Republican candidate, who's a multibillionaire, and Michael Bloomberg became an independent candidate, who's a multibillionaire, and it will tell people what I have been saying for a long time.

That this country is moving away from democracy to oligarchy.

That billionaires are the people controlling our political life. That is not what American democracy is supposed to be about -- a contest between billionaires, if that takes place, I am confident I will win it.