Former Vice President Joe Biden’s initial pitch to Democratic voters was aimed squarely at the Rust Belt working class, but on a weekend trip through South Carolina, the early frontrunner for the party’s presidential nomination pivoted to courting black voters in the Palmetto State, highlighting his role in the Obama administration and warning of voting restrictions that hark back to the days of Jim Crow.

“Last year, 24 states introduced or enacted at least 70 bills to curtail the right the vote. And guess what—mostly directed at people of color,” Biden told the crowd at a community center in Columbia, South Carolina on Saturday. “We have Jim Crow sneaking back in.”

“You know when everybody has an equal right to vote, guess what—they lose. They lose,” Biden continued, referring to Republicans, whose victories in statewide elections in nearby Georgia and Florida last year sparked accusations of systematic voter suppression. “Folks, it’s just absolutely wrong.”

By highlighting the importance of expanding voter access, as well as his long relationship with President Barack Obama—in his speech, Biden referred to Obama as “my buddy” and “my friend” multiple times before joking that “I shouldn’t be so casual”—Biden pitched himself as a candidate with a broader coalition of supporters beyond the white working class. But the former vice president’s history as an architect of the modern criminal justice system has activists and academics concerned that Biden hasn’t sufficiently addressed the legacy of mass incarceration in marginalized communities.

Biden, who served in the U.S. Senate for three decades, was a driving force behind the implementation of aggressive criminal justice policies in the 1980s and 1990s, culminating in the writing and passage of the Violent Crime Control and Law Enforcement Act of 1994, which he himself dubbed the “1994 Biden Crime Bill” in 2015.

Now, 25 years after the passage of this landmark bill, criminal justice advocates say the policy led to mass incarceration that disproportionately affected black communities and are calling on him to undo that legacy in order to win their support.

“He’s in a precarious situation,” said Dr. Keneshia Grant, a professor of political science at Howard University whose research focus is the political impact of black migration in the United States. “He absolutely has to be saying things like, ‘people’s attempts to disenfranchise you is like Jim Crow,’ but that creates a difficult situation for him.”

“The ’94 crime bill helped shape crime policy for almost the next 20 years,” said Nicole D. Porter, director of advocacy at the Sentencing Project, a Washington-based nonprofit that seeks to address racial disparities in the criminal justice system. “It was adopted at a time when the approach to crime was very punitive—there was little resistance to adopting tougher penalties at the federal and at the state level, particularly in communities that were undergoing disinvestment.”

The legislation, signed into law by President Bill Clinton, was the largest crime bill in American history, and included a (since expired) ban on assault weapons, the Violence Against Women Act, and created guidelines for states to track sex offenders. But the bill included controversial provisions, including a so-called “three strikes” provision, the elimination of Pell Grants for incarcerated inmates, and provided nearly $10 billion for the construction of new prisons. The bill also increased incentives for states to sentence criminals to longer sentences, leading to an era of mass incarceration: More than 2 million Americans are currently imprisoned.

“It’s not that he was swept up on the tough on crime—he drove the train. He was chair of the Judiciary Committee, he wrote a lot of these bills,” Michael Collins, director of national affairs for Drug Policy Action, told The Daily Beast. “The ‘War on Drugs’ has always been a war on people of color—we knew that back in the 1990s, and it didn’t stop Joe Biden then, and this is why we have this mass incarceration mess right now.”

Biden’s legacy on criminal justice may complicate efforts to capitalize on high initial approval ratings among black voters, who make up more than half of registered Democrats in South Carolina.

“He’s going to have to run a very issue-oriented campaign if he’s going to win black voters in South Carolina. He can’t just show up and say, I was Barack Obama’s vice president, because that ain’t going to work,” former South Carolina state legislator Bakari Sellers, who has endorsed Sen. Kamala Harris (D-CA) for president, told The Daily Beast.

“I find it ironic that Hillary [Clinton] got pure hell for the ’94 crime bill when Joe Biden actually wrote the ’94 crime bill,” Sellers said. “He’s going to have to answer those questions, and he’s going to have to answer with policy points… He has to reconcile with his record, and he’s not answering those questions now.”

Advocates were quick to point out that as the Democratic consensus on criminal justice has changed, so too have Biden’s views—to a point.

“Biden has followed the politics on this issue,” Porter said. “As vice president in 2010, he anchored a reform... to scale back the 100-to-one crack cocaine-to powder disparity.”

The former vice president has indicated that there are certain positions he has taken on crime that he now disavows. At the National Action Network’s Martin Luther King Jr. breakfast in January, Biden said that on criminal justice reform, “I know we haven't always gotten things right, but I’ve always tried,” alluding to the crime bill as “a big mistake when it was made.”

But undoing the legacy of “tough-on-crime” legislation, criminal justice reform advocates said, requires more than an apology.

“A stopped clock can be right twice a day, but when you look at the totality of Biden’s career, he has been one of the top cheerleaders in the War on Drugs,” Collins said. “The only reason we’re seeing any contrition here is because he’s running for president—if he was retired, we wouldn’t be seeing apologies or any of these explanations.”

If Biden is serious about mitigating his role in the modern carceral state, Sellers said, he’ll begin detailing concrete policy proposals to “unravel some of the damage that he’s done.”

“Moving forward, when he does talk about criminal justice, he’s going to have to talk about it in ways that are first, apologetic, and two, super clear about policy proposals to mitigate the effects of his past positions,” Grant echoed.

To “account for the harm done in this country during the era of mass incarceration,” Porter suggested the elimination of mandatory minimums across the board, redirecting resources to focus on crime prevention and helping people who exit the prison system successfully enter into society, and full sentencing parity in drug possession cases—as well as provisions making such changes retroactive.

“It would take 75 years for the country to get back to the incarceration rates of the early ’80s” at current rates of release, Porter said, which means that undoing mass incarceration requires policies “as substantial and muscular as the politics that drove the punitive reforms in the ’80s and ’90s.”

The Biden campaign did not respond to a request for comment on the former vice president’s views on such proposals by press time.

There is historical precedent for a president undoing the damage caused by previous positions and policies, Grant said, citing the case of President Lyndon Johnson, who signed the Civil Rights Act and the Voting Rights Act into law.

“Lyndon Johnson starts out as a legislator who is not particularly helpful in the civil rights movement,” Grant noted. “Now when you think about him and think about his evolution on race, you can point to the Civil Rights Act to say, this is something he did to make up for his past or change his trajectory.”