Harvard University philosopher Cornel West says Democratic front-runner Joe Biden will lose black voters to President Trump if he doesn't "get off his symbolic crack pipe" and stop defending the 1994 crime law that he authored.

West, a prominent left-wing activist, spoke with the Washington Examiner after Trump tweeted Monday that blacks "will not be able to vote" for politicians associated with the law, which Biden defended this month by saying it "did not generate mass incarceration."

"I hope and pray he is unable to do it. But if Trump comes out strong on criminal justice reform, he is going to get a slice of the black vote, because this is life or death," West said. "I think Biden is going to have to take responsibility and acknowledge the contribution he made to something that was not a force for good. We all make mistakes, but this was a major, major bad judgment. And we have to tell the truth.

"That Joe Biden was one of the architects, or core architects, is going to haunt him in a very serious way," West said. "When he says it didn't contribute to mass incarceration, I tell him he has to get off his symbolic crack pipe."

The 1994 law introduced mandatory life sentences for three-time federal felons and had a ripple effect of increasing state prison populations by granting $12.5 billion for prison construction to states that passed "truth-in-sentencing" laws forcing inmates to serve 85% of sentences.

In his Twitter assault, Trump wrote that the First Step Act he signed in December — lessening the three-strikes penalty to 25 years, among other reductions — "helped fix the bad 1994 Bill" and noted that then-first lady Hillary Clinton used the term "super predator" to describe black youth targeted by the measure.

"Super Predator was the term associated with the 1994 Crime Bill that Sleepy Joe Biden was so heavily involved in passing. That was a dark period in American History, but has Sleepy Joe apologized? No!" Trump wrote.

West largely agreed with Trump's attack on Biden and expressed concern about the former vice president fracturing the Democratic base ahead of 2020. West, who supports Vermont Sen. Bernie Sanders over Biden, said that large numbers of black voters and progressives would sit out the election if Biden were unrepentant as the Democratic nominee.

"It is our relatives and friends and children who were damaged by this," West said of the crime bill, explaining why African Americans would abandon Biden. "I think it damaged sister Hillary also" in 2016

West said Biden "should be ashamed of himself" for using the word "predator" in a 1993 speech pushing for the legislation, and that Trump has a clear political opening.

West said Biden will cause many liberal voters, as well as black voters, to abandon him if he does not apologize for the 1994 law. Sanders also voted for the bill but said in March he was swayed by the inclusion of an assault weapons ban and provisions penalizing violence against women.

West said "we got to do everything we can to get brother Trump out of the White House," suggesting with a laugh, "My fundamental advice to Biden is pull out of the race and pull into the port of Bernie."

Anyone associated with the 1994 Crime Bill will not have a chance of being elected. In particular, African Americans will not be able to vote for you. I, on the other hand, was responsible for Criminal Justice Reform, which had tremendous support, & helped fix the bad 1994 Bill! — Donald J. Trump (@realDonaldTrump) May 27, 2019

Other liberal activists responded favorably to Trump introducing criminal justice reform as a campaign issue, but side-stepped attacking Biden.

“It’s unclear yet how much criminal justice reform issues will be an influential factor in the 2020 election, but it certainly should be,” said Ed Chung, vice president for criminal justice reform at the liberal Center for American Progress Action Fund.

Alveda King, the conservative evangelical leader and niece of Martin Luther King Jr., said many lawmakers changed their views after observing negative effects of the crime bill, but she sees Biden as unapologetic, undermining his standing among "not just black people, but people of conscience."

“Joe Biden is not repentant. From a spiritual perspective for his own soul he needs to repent," King said.

“Enough people do not know [about the law], and when they do find out they definitely care," she said. "I believe an enlightened, compassionate America will vote for those who want to set the captives free.”

....Super Predator was the term associated with the 1994 Crime Bill that Sleepy Joe Biden was so heavily involved in passing. That was a dark period in American History, but has Sleepy Joe apologized? No! — Donald J. Trump (@realDonaldTrump) May 27, 2019

Mamie Locke, a Democratic state senator in Virginia who teaches politics at historically black Hampton University, said she believes Trump's own past limits his appeal, pointing to his advocacy of the death penalty for the falsely accused Central Park Five and saying there were good people on "both sides" of the 2017 protests surrounding a Confederate statue in Charlottesville, Va.

But Locke said by raising the crime bill, Trump may upset black voters, prompting some to stay home in 2020.

"I think that's Trump's purpose in raising this, to suppress voter turnout," Locke said.

Biden's campaign did not return a request for comment.