Democratic presidential candidate and U.S. Sen. Bernie Sanders pauses to talk to the media before the start of the Milford Labor Day Parade in Milford, New Hampshire, Sept. 7, 2015. Reuters

Has Warren Buffett joined the Bernie Sanders bandwagon? The billionaire investor and Berkshire Hathaway chief executive Tuesday praised the U.S. senator from Vermont who is running for president against Democratic front-runner Hillary Clinton.

"I think Bernie Sanders has been a terrific campaigner. He campaigns exactly as I would campaign if I were a candidate," Buffett said in an interview on CNBC. Buffett pointed to Sanders' refusal to criticize Clinton and his opposition to political spending by corporations and unions.

"He's not going around saying things about other people. He's just saying, 'Here's my program,' " Buffett said. "I think he's run a model campaign. He's not going to get elected, but I admire him."

Bernie Sanders Presidential Candidate Profile | InsideGov

Buffett previously pledged to vote for Clinton and donated to the "Ready for Hillary" group in 2014. He chided Clinton Tuesday for dismissing critics who have raised questions about her use of a personal email address and private server while she was secretary of state.

"I don't think it was the best way to handle it," Buffett said.

Buffett also said he was keeping his eye on Republican front-runner Donald Trump, who has made headlines for a series of provocative and comical comments, including reassuring voters that his hair is not fake. "How can you not watch him?" Buffett asked, laughing.

A Monmouth University poll released Tuesday indicates 42 percent of Democrats back Clinton while 20 percent favor Sanders. Clinton's favorability rating has held strong at 71 percent favorable, 17 percent unfavorable.

Sanders has remarked on Buffett's support for Clinton in the past. “Is Hillary Clinton -- are other candidates -- prepared to take on the billionaire class?” he asked during a meeting with Bloomberg editors and reporters in April. “Based on her record, I don’t” believe she is, he said at the time, pointing to Clinton's relationship with Buffett. He also called Buffett's wealth “obscene” when compared with the average U.S. household.