Warren Buffett speaks onstage during Fortune's Most Powerful Women Summit - Day 2 at the Mandarin Oriental Hotel on October 13, 2015 in Washington, DC.
Paul Morigi—2015 Getty Images
Updated: December 16, 2015 3:21 PM ET | Originally published: December 16, 2015 1:15 PM EST

Billionaire Warren Buffett took a few sly shots at Donald Trump while campaigning for Hillary Clinton in Omaha on Wednesday.

The former Secretary of State “is very very smart. And there are plenty of other candidates, well, not too many others, who are probably as smart,” Buffett said to laughter from the crowd at the Sokol Auditorium. “In fact, one talks about every five minutes how smart he is. And incidentally I went to Wharton too and I left after two years to go to the University of Nebraska.”

Buffett was the world’s third richest man in 2015 worth an estimated $63 billion. By comparison, Trump was worth an estimated $4 billion in 2015.

Buffett also poked fun at Tuesday night’s Republican debate. “I’ve listened to all Republican debates. I used to love Abbott and Costello,” she said, shaking his head ruefully. “I mean I’m reliving my youth: vaudeville was never this good.”

Buffett has never been a political godfather, despite repeated entreaties from the left to step in as the power of the right’s billionaires such as the Koch brothers and Sheldon Adelson, has risen. Indeed, his involvement in politics has remained tepid: in 2008 he held fundraisers for both Hillary Clinton and Barack Obama, but declined to endorse either. His biggest political move has been on the policy front: introducing the so-called Buffett rule that called for an overhaul of a tax code that allowed him to pay less taxes than his secretary.

Which is what makes Buffett’s endorsement and support of Clinton so exceptional. Buffett noted that in 1992 the top 400 earners made an average of $46.8 million and paid 26.3% in taxes but 20 years later by 2012 the top 400 earned $335.7 million and paid on average 16.7% in taxes.

“Despite incredible bounty, millions and millions of Americans have been left behind,” Buffett told the boisterous crowd, his second day of events with her this month. “These are numbers that Secretary Clinton won’t forget in office, which is the primary reason why I’m going to be so delighted when Secretary Clinton takes the oath of office.”

Clinton has pledged to not increase taxes on families earning less than $250,000 a year as president. “We’re out of balance. The deck is stacked for those at the top and we need to reshuffle the deck,” Clinton told the crowd.

Though he’s not exactly signing over millions a la the Koch brothers, Buffett is getting more involved this cycle than in any election past. His fundraiser in New York last week for Clinton drew Wall Street types willing to pay $33,400 for the former First Lady and Secretary of State. And on Wednesday morning before the rally in Omaha the pair held a second fundraiser where tickets ranged from $500 to $2,700—the max an individual is allowed to donate under federal rules—and as much as $27,000 for a photo with Buffett and Clinton.

A spokesman for the Republican National Committee criticized Clinton for campaigning with Buffett.

“Campaigning with the third richest person on the planet is an odd way to communicate that she understands and cares about the needs of millions of Americans still struggling in the weak Obama economy,” he said.

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