Bernie Sanders said he would hammer at Pete Buttigieg's contributions from wealthy donors in the last few days of campaigning before Tuesday's New Hampshire primary.
"At last count he has about 40 billionaires who are contributing to his campaign," the Vermont senator told CBS's "Face the Nation" on Sunday.
"It matters enormously. That is precisely the problem with American politics."
"Do you really think that when someone gets contributions from the CEOs of pharmaceutical companies, he's going to stand up to the greed and corruption of that industry?" Sanders said.
Sanders conceded that the messy Iowa caucus system - which has yet to produce a final result after six days of counting - is a "sad state of affairs". But he insisted that he won the state regardless of the number of delegates to come out of Iowa because he won the popular vote by 6 000 votes.
Still, he said he would support Buttigieg if the former South Bend, Indiana, mayor is the eventual Democratic nominee. "I have said from the first day of this campaign that it is imperative that we defeat Donald Trump. Of course I'll support the nominee."
Sanders continued to push his Medicare for All plan. Although he wouldn't be pinned down on an exact cost, he didn't dispute an estimated price tag of $30 trillion to $40 trillion over 10 years. "Anybody who tells you what anything is going to cost is not telling you the truth. It's so much. It's so big."
*Disclaimer: Michael Bloomberg is also seeking the Democratic presidential nomination. He is the founder and majority owner of Bloomberg, the parent company of Bloomberg News.