In January 2021, the person inhabiting the White House has to be a progressive, Robert Kuttner, the co-founder of The American Prospect, said during an interview with Boston Public Radio on Tuesday.

In his new book, “The Stakes: 2020 and the Survival of American Democracy,” Kuttner outlines his case for why President Donald Trump needs to be defeated in 2020, and how a progressive candidate like Sens. Bernie Sanders or Elizabeth Warren can do it. According to Kuttner, the biggest danger Trump poses to the United States is his willingness to manipulate law enforcement agencies to do his political bidding.

“It took him two and a half years to get an [Attorney General] in Bill Barr, who is his personal errand boy,” Kuttner said. “Little by little by little, you take over the police agencies. You turn the FBI, the CIA, the NSA into your personal police forces.”

The biggest threats to a Warren or Sanders presidency, Kuttner thinks, are each other. His hope is that the two campaigns do not compete too heavily with each other and leave the pathway to the nomination open for a more moderate candidate.

“My only worry is that Sanders and Warren do each other in,” Kuttner said. “I mean, talk about an embarrassment of riches. It’s been 50 years since we’ve had even one progressive as as serious contender of the nomination.”

Kuttner is the Meyer and Ida Kirstein Visiting Professor in Social Planning and Administration at Brandeis University.