At the Democratic debate on Wednesday night, Democratic candidates ranging from Cory Booker to Julián Castro hit Joe Biden for his long, punitive record on criminal justice.

Biden’s record puts him at sharp odds with where Democrats are today: He has one of the most punitive, “tough on crime” records on criminal justice issues within the 2020 field — more so than even opponents Kamala Harris or Amy Klobuchar, both of whom have also been criticized for their records. In fact, Biden was at the center of building federal policies that escalated the war on drugs and mass incarceration.

Consider one moment in Biden’s career: In 1989, at the height of punitive anti-drug and mass incarceration politics, Biden, then a senator, went on national television to criticize a plan from President George H.W. Bush to escalate the war on drugs. The plan, Biden said, didn’t go far enough.

“Quite frankly, the president’s plan is not tough enough, bold enough, or imaginative enough to meet the crisis at hand,” he said. He called not just for harsher punishments for drug dealers but to “hold every drug user accountable.” Bush’s plan, Biden added, “doesn’t include enough police officers to catch the violent thugs, not enough prosecutors to convict them, not enough judges to sentence them, and not enough prison cells to put them away for a long time” — a direct call for more incarceration.

As the head of the Senate Judiciary Committee in the late 1980s and early ’90s, Biden did not just support the war on drugs and mass incarceration; he wrote many of the laws that helped build a punitive criminal justice system. That included measures that enacted more incarceration, more prisons, and tougher prison sentences for drug offenses, particularly crack cocaine.

Much of this matched the rhetoric of the day, when Democrats and Republicans in the ’80s and ’90s pushed for lengthier prison sentences and “tough on crime” policies in general to combat a crime wave and a crack cocaine epidemic.

But as Democrats have since evolved on criminal justice issues to support reforms that reel back the war on drugs and incarceration, Biden’s record puts him at odds with where much of the party is today — with polls showing that most Democrats and most of the public back at least some reforms.

“There’s a tendency now to talk about Joe Biden as the sort of affable if inappropriate uncle, as loudmouth and silly,” Naomi Murakawa, author of The First Civil Right: How Liberals Built Prison America, told the Marshall Project in 2015. “But he’s actually done really deeply disturbing, dangerous reforms that have made the criminal justice system more lethal and just bigger.”

Biden has backtracked since the ’80s and ’90s. Before he left the Senate to become vice president, he pushed to pull back tougher prison sentences for crack cocaine — an effort that helped lead to a law that President Barack Obama signed in 2010. And he’s recently acknowledged his mistakes.

“I haven’t always been right,” Biden said earlier this year, speaking to criminal justice issues. “I know we haven’t always gotten things right, but I’ve always tried.” (Asked about Biden’s record, his spokesperson pointed to this speech, but did not respond to further questions.)

As a former vice president for a still-popular administration, Biden currently has very good standing among Democrats. National polls of the 2020 primary consistently put him at the top of the pack, leading all the other candidates who have announced so far. He also has fairly high favorability ratings; a recent survey from YouGov and the Economist found that “he is the sole Democratic contender whose overall favorability ratings are positive,” scoring very high numbers among Democrats in particular.

But Biden also faces a Democratic constituency that has, during his time in the public spotlight, changed dramatically on criminal justice issues. He spent years promoting “tough on crime” policies that led to mass incarceration — and now Democrats want the direct opposite, supporting an end to mass incarceration, the war on drugs, and aggressive policing. How Biden navigates the conflict between his past and his party’s present could help decide if he becomes the party’s nominee for president.

Biden didn’t just support the war on drugs. He authored large chunks of it.

During the 1980s and ’90s, America was in the middle of a crack epidemic and a huge crime wave. In response to this, Republicans and Democrats competed to look “tough on crime” — enacting incredibly punitive policies at all levels of government that focused, in large part, on imprisoning as many people as possible. On the Republican side, these efforts were led by Ronald Reagan and George H.W. Bush. But on the Democratic side, Biden, as head of the Senate Judiciary Committee, was a major leader in these efforts.

He clashed with Bush throughout the late 1980s and early ’90s about crime and drugs — Bush would put out a proposal and Biden would try to go further. During a debate over a bill in 1991 (that would eventually become the 1994 crime law), Biden argued his plan was “much tougher than the president’s” and “provides for more penalties for death for more offenses than the [president’s] bill.” In response to Republican criticisms that his bill protected criminals, Biden claimed that “we do everything but hang people for jaywalking.”

In between the political squabbles, though, Biden really did help enact some very punitive legislation. Here are some examples from his record, drawn partly from Jamelle Bouie’s previous rundown at Slate:

Comprehensive Control Act : This 1984 law, spearheaded by Biden and Sen. Strom Thurmond (R-SC), expanded federal drug trafficking penalties and civil asset forfeiture, which allows police to seize and absorb someone’s property — whether cash, cars, guns, or something else — without proving the person is guilty of a crime.

This 1984 law, spearheaded by Biden and Sen. Strom Thurmond (R-SC), expanded federal drug trafficking penalties and civil asset forfeiture, which allows police to seize and absorb someone’s property — whether cash, cars, guns, or something else — without proving the person is guilty of a crime. Anti-Drug Abuse Act of 1986 : This law, sponsored and partly written by Biden, ratcheted up penalties for drug crimes. It also created a big sentencing disparity between crack and powder cocaine; even though the drugs are pharmacologically similar, the law made it so someone would need to possess 100 times the amount of powder cocaine to be eligible for the same mandatory minimum sentence for crack. Since crack is more commonly used by black Americans, this sentencing disparity helped fuel big racial disparities in incarceration.

This law, sponsored and partly written by Biden, ratcheted up penalties for drug crimes. It also created a big sentencing disparity between crack and powder cocaine; even though the drugs are pharmacologically similar, the law made it so someone would need to possess 100 times the amount of powder cocaine to be eligible for the same mandatory minimum sentence for crack. Since crack is more commonly used by black Americans, this sentencing disparity helped fuel big racial disparities in incarceration. Anti-Drug Abuse Act of 1988 : This law, co-sponsored by Biden, strengthened prison sentences for drug possession, enhanced penalties for transporting drugs, and established the Office of National Drug Control Policy, which coordinates and leads federal anti-drug efforts.

This law, co-sponsored by Biden, strengthened prison sentences for drug possession, enhanced penalties for transporting drugs, and established the Office of National Drug Control Policy, which coordinates and leads federal anti-drug efforts. Violent Crime Control and Law Enforcement Act: This 1994 law, partly written by Biden, imposed tougher sentences and increased funding for prisons, contributing to the growth of the US prison population from the 1990s through the 2000s — a trend that’s only begun to reverse in the past few years. It also included other measures, such as the Violence Against Women Act that helped crack down on domestic violence and rape, a 10-year ban on assault weapons, funding for firearm background checks, and grant programs for local and state police.

In short, Biden helped write and pass two of the most important pieces of federal legislation in the federal war on drugs — the 1986 and 1988 laws — and, in particular, helped create the sentencing disparity for crack and powder cocaine. And he was at least partly behind other laws that perpetuated mass incarceration and increased police powers. (A caveat: The great majority of incarceration happens at local and state levels, where federal law doesn’t apply.)

As Washington Post opinion writer Radley Balko tweeted in 2015, “The martial/incarceral state has had no greater friend in Washington over the last 35 years than Joe Biden.”

This reflected the politics of the time, as Democrats competed with Republicans to look as tough as possible on crime. It was a Democratic president, Bill Clinton, who signed the 1994 crime law that Biden helped write. That was largely a response to public demand: Based on Gallup’s surveys, people were much more likely, particularly in the 1990s, to say that crime was the most important issue facing the country.

Since the mid-2000s, this has started to shift in the Democratic Party. With books like The New Jim Crow by Michelle Alexander and movements like Black Lives Matter, the party has especially paid attention to the vast racial disparities in the criminal justice system that make it more likely a black man will be locked up for longer for the same crimes as a white man.

It’s in this new context that Biden’s record starts to look very dated. While other politicians can claim that they were simply following the politics of the time, or say they never supported mass incarceration to begin with, Biden was a leader in this space — and he earnestly and enthusiastically pursued mass incarceration and the war on drugs.

Biden has tried to repent for some of his past

Even before talk of his presidential run, and even before he became vice president, Biden did begin to distance himself from his past “tough on crime” record.

In 2008, he backed the Second Chance Act, which provides monitoring and counseling services to former prison inmates. In his last few years in the Senate, he supported the full elimination of the sentencing disparity between crack and powder cocaine. (The disparity was reduced from 100-to-1 to 18-to-1 in 2010 with the passage of the Fair Sentencing Act of 2010.)

Biden even offered somewhat of an apology during a 2008 Senate hearing:

Many have argued that this 100-to-1 disparity is arbitrary, unnecessary, and unjust, and I agree. And I might say at the outset in full disclosure, I am the guy that drafted this legislation years ago with a guy named Daniel Patrick Moynihan, who was the senator from New York at the time. And crack was new. It was a new “epidemic” that we were facing. And we had at that time extensive medical testimony talking about the particularly addictive nature of crack versus powder cocaine. And the school of thought was that we had to do everything we could to dissuade the use of crack cocaine. And so I am part of the problem that I have been trying to solve since then, because I think the disparity is way out of line.

He echoed the same apology recently, telling attendees at a breakfast commemorating Martin Luther King Jr. in January that “it was a big mistake when it was made. We thought, we were told by the experts, that crack, you never go back; it was somehow fundamentally different. It’s not different.”

And in July, Biden released a sweeping criminal justice reform plan that included, among other proposals, decriminalizing marijuana, eliminating mandatory minimum sentences for nonviolent crimes, ending the death penalty, abolishing private prisons, getting rid of cash bail, and discouraging the incarceration of children. The goal, Biden’s campaign said, was to cut incarceration and fix “the racial, gender, and income-based disparities in the system.”

Biden’s supporters also point out that he was never totally on board with some of the harsher measures in previous laws. For example, in a 1993 symposium sponsored by the US Sentencing Commission, Biden argued for undoing some mandatory minimums for drug offenses. “I think we’ve had all the mandatory minimums that we need. We don’t need the ones that we have,” he said. “But quite frankly, I don’t think I will prevail … I’ve watched how the process works. I am not at all hopeful there will be [enough] senators prepared to vote with me.”

This wasn’t just talk, Biden’s office previously told me. The 1994 law ultimately included what’s called a “safety valve” that allows a very limited number of low-level first-time drug offenders to avoid mandatory minimum sentences. This part of the 1994 law — along with the Violence Against Women Act, the 10-year ban on assault weapons, funding for firearm background checks, and grant programs for local and state police, which were all part of the 1994 measure — were some of the big-ticket items that led Biden to back the bill, even though he didn’t support every part of it, his office previously claimed.

But Biden has seemed proud of the 1994 law, even some of its “tough on crime” measures, until fairly recently. In his 2008 presidential campaign website, Biden’s campaign called the 1994 law the “Biden Crime Law.” And the website proudly touted a funding program in the law that encouraged states to effectively increase their prison sentences by paying them to build more prisons — a direct endorsement of more incarceration.

And in 2016, after CNBC asked Biden if he was ashamed of the 1994 law, Biden responded, “Not at all. As a matter of fact, I drafted the bill, if you remember.” He acknowledged that there were parts of the law he’d change, but argued that “by and large what it really did, it restored American cities.”

The effects of Biden’s actions are still felt today. When Trump called for greater use of the death penalty to fight the opioid epidemic, then–Attorney General Jeff Sessions cited the 1994 crime law that Biden worked to pass to put legal weight behind Trump’s plan.

There’s way less ambiguity in Biden’s record than in his opponents’ pasts

Other presidential candidates have faced similar criticisms for their “tough on crime” records, including Sen. Kamala Harris (D-CA) for her work as a prosecutor and California’s attorney general and Sen. Amy Klobuchar (D-MN) for her time as a prosecutor in Minnesota.

But there are some nuances to these criticisms. Both Harris and Klobuchar did pursue some “tough on crime” policies, such as going after nonviolent offenders in certain cases. But Harris was also ahead of her time in, for example, supporting a “Back on Track” program that allowed first-time drug offenders to get a high school diploma and a job instead of prison time. And Klobuchar, while mostly an of-the-time “tough on crime” prosecutor in Hennepin County, worked with the Innocence Project to push for reforms in eyewitness identification and recorded police interviews — two big causes of the innocence movement at the time.

Biden’s record is much more straightforward. Sure, he occasionally spoke out against some tough measures, and some of his proposals included more funding for addiction treatment. But taken as a whole, Biden was very clearly and consistently pushing to make the criminal justice system much more punitive. His main criticisms of Bush and other Republicans were specifically that they weren’t “tough enough.”

As he said, touting the 1994 crime law:

The liberal wing of the Democratic Party is now for 60 new death penalties… The liberal wing of the Democratic Party has 70 enhanced penalties... The liberal wing of the Democratic Party is for 100,000 cops. The liberal wing of the Democratic Party is for 125,000 new state prison cells.

It remains unclear just how big an issue this will be for Biden. Various polls, including one from Vox and Morning Consult, have found the majority of Democrats support at least some criminal justice reform efforts. But other surveys, like Gallup’s, have also found that criminal justice issues aren’t a top-tier issue for voters — falling behind, in recent times, concerns about the government and poor leadership, immigration, the economy, and race relations.

Still, his record is bad news for criminal justice reformers. A constant worry in the criminal justice reform space is what would happen if, say, the crime rate started to rise once again. If that were to happen, there could be pressure on lawmakers — and it’d at least be easier for them — to go back to “tough on crime” views, framing more aggressive policing and higher incarceration rates in a favorable way.

Given that the central progressive claim is that these policies are racist and, based on the research, ineffective for fighting crime in the first place, any potential for backsliding in this area once it becomes politically convenient is very alarming.

The concern, then, is what would happen if crime started to rise under President Biden: Would he fall back on old “tough on crime” instincts, calling for harsh prison sentences once again?

“[E]ven if Biden has subsequently learned the error of his ways,” Branko Marcetic wrote for Jacobin, “the rank cynicism and callousness involved in his two-decade-long championing of carceral policies should be more than enough to give anyone pause about his qualities as a leader, let alone a progressive one.”

If enough Democrats come to that view, it could threaten Biden’s chances of becoming the next president of the United States.