Bernie Sanders' latest high-profile endorser on Monday predicted that if a progressive doesn't win the presidency, the U.S. will have to deal with "another Donald Trump down the road." Washington Representative Pramila Jayapal warned that a moderate like former Vice President Joe Biden would not go far enough in transforming the country.

"Even if it is a Democratic president, if we don't address these issues we will end up with another Donald Trump down the road," the Democratic congresswoman told CBS News. "Because people are suffering. And our job has to be to fix that suffering."

Jayapal endorsed Sanders for president Sunday, a notable win for the Sanders campaign over fellow progressive Senator Elizabeth Warren. Jayapal told CBS News that she chose Sanders over Warren because of a shared history of organizing she has with the Vermont senator.

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"At the end of the day, I think for me it came down to the fact that Bernie Sanders is like me: an organizer," Jayapal explained. "He believes the change that we need is bold and big, and institutional, but it doesn't happen without building a broader movement."

Jayapal said Sanders "understands the urgency of the moment" and used the occasion of Martin Luther King Jr. Day to compare Sanders' vision to that of the civil rights icon.

"He understands ... that tranquilizing drug of gradualism is not the way forward," Jayapal said, referencing a quote from Dr. King's famous "I have a dream" speech.

Asked if she informed Warren about endorsing Sanders over her, Jayapal confirmed that she called Warren before making her official announcement.

"I am endorsing fully Bernie Sanders. But if there comes a time when we have to come together behind Elizabeth Warren, of course we're gonna do that, and of course we're gonna back any Democrat that is running against Donald Trump," she said. "But this is our moment. This is our chance to turn this country around, and I really believe that Bernie Sanders is the guy that's gonna do that with us."

Jayapal, the co-chair of the House Progressive Caucus, said Biden is a much different kind of candidate than either Sanders or Warren.

"I don't think the [former] vice president would call himself a progressive," she said. "It's about understanding that while it might sound more comforting to people to have gradual change, and just do small tweaks because it feels...less disruptive, the truth is, we have deep structural inequities in the system today."