The presidential candidacy of Vermont senator Bernie Sanders “has the potential to be a dangerous moment,” according to Lloyd Blankfein.

The chairman and CEO of investment bank Goldman Sachs told CNBC yesterday (Feb. 3) that Sanders’s angry rhetoric against the financial industry has wide implications, “not just for Wall Street, not just for the people who are particularly targeted, but for anybody who is a little bit out of line.” He added: “It’s a liability to say I’m going to compromise, I’m going to get one millimeter off the extreme position I have and if you do you have to back track and swear to people that you’ll never compromise. It’s just incredible. It’s a moment in history.”

Any criticism coming from one of the world’s most prominent bankers will likely bolster Sanders’s appeal among his supporters. Journalist Glenn Greenwald called it “the most powerful endorsement yet” for the campaign.

Meanwhile, former secretary of state Hillary Clinton is struggling to justify her ties to the bank, which is a lightning rod for critics of Wall Street. Asked by CNN’s Anderson Cooper why she accepted $660,000 in speaking fees from Goldman, she said: “Well, I don’t know. That’s what they offered.”