Sen. Bernie Sanders (I-Vt.) thinks Donald Trump’s personal vendettas could lead to the collapse of American democracy.

Sanders told The Guardian he believes the “bitter” and “humiliated” ex-president would be more vindictive than ever, if elected for a second term later this year.

“He’s made that clear,” Sanders said in an interview published Saturday. “There’s a lot of personal bitterness, he’s a bitter man, having gone through four indictments, humiliated, he’s going to take it out on his enemies.”

With the stakes that high, the senator said it was essential “to explain to the American people what that means to them ― what the collapse of American democracy will mean to all of us.”

While Sanders said he thinks another Trump presidency would be catastrophic for the country, he told The Guardian he could see why Trump’s strongman persona spoke to so many Americans.

“Trump comes along and says, ‘I’ll be your strong guy, I’ll deal with all your anxieties ― immigration, transgender issues, race ― I’ll be there for you,’” the senator said of the former president’s appeal.

Though he worried about how a second Trump term would affect Americans, Sanders told the outlet he does not “believe that all of Trump’s supporters are racist or sexist or homophobes.”

“I think what’s going on in this country is a belief that the government is failing ordinary Americans,” he went on.

The presumptive Republican presidential nominee has been outpolling his competitors by double digits. An ABC/Ipsos poll released Sunday found that 72% of Republican-aligned adults would be satisfied with Trump as the nominee.

That popularity will be put to the test on Monday, when elections officially begin with the Iowa caucus.