Opinion | Trump Corrupted the Presidential Pardon. Biden Must Repair It.

The first and most important step: Take back control of the pardon process. The power to grant mercy may be the president’s alone, but the office of the pardon attorney operates out of the Justice Department. As a result, before any request for clemency can land on the president’s desk, it has to survive review by a gantlet of people whose job it is to win convictions, not undo them. In some cases, the same prosecutors who sent a person to prison are asked to weigh in on granting that person mercy. It’s “akin to having Yankees fans pick the Red Sox’s starting pitcher,” wrote Mark Osler, a law professor at the University of St. Thomas School of Law who advocates for comprehensive clemency reform.

Prosecutors’ built-in biases are exacerbated by the fear of public blowback if any grant of clemency goes wrong — say, if a person commits a crime after being granted relief.

The gulf between presidents and their pardon decisions has confounded executives of both parties. One of the last pieces of advice the outgoing President George W. Bush gave the incoming President Barack Obama was to pick a pardon policy and stick to it. Mr. Obama didn’t heed the warning. He dithered for years before finally developing clear clemency standards late in his second term. The result: mercy for more than 1,900 people, many of them serving absurdly long sentences for low-level drug crimes. That was very good, but as long as the Justice Department maintains control over the process, it easily reverts to form, as it has under Mr. Trump.

It’s not enough simply to bring the process back into the White House. Mr. Osler has proposed the establishment of a clemency board or commission with a direct line to the president, and staffed with experts in the field of criminal justice rather than with politicians worried about how their decisions might affect their electoral prospects. Board members should reflect the nation’s diversity in terms of race, geography and political ideology. Nearly all states incorporate the work of a board or commission in their clemency processes; not coincidentally, states generally do a much better job of handling their petitions than the federal government does.

Mr. Biden could create and staff a clemency board by executive order. He could also avoid Mr. Obama’s mistake by laying out clear, consistent standards for considering petitions early in his administration. What the Justice Department currently considers — the seriousness of the crime, whether the offender has expressed remorse and shown rehabilitation — is reasonable, but it often isn’t reflected in clemency decisions.

Congress has an important role to play too. The pardon power is vast but not without limits. For instance, presidents may not violate core constitutional rights with their pardons, dangle pardons as a way to evade the justice system or offer mercy in exchange for bribes. Some constitutional scholars say they may not pardon themselves, although no president has yet tried to. To remind presidents that they are being watched, Congress can require the White House to issue a regular clemency report, as many states require of their governors today. It may also investigate individual pardons for possible abuse, as it did after Mr. Clinton’s pardon of Mr. Rich. And it can impose consequences, up to and including impeachment.

Speaking of impeachment, Mr. Trump has a few weeks left in office, during which he could choose to make at least some amends for his degradation of the pardon power by, say, considering the petitions of even some of the thousands of people still waiting. We’re not holding our breath. Real reform is more likely to come from Mr. Biden, who has his own amends to make. As a senator, Mr. Biden helped draft and championed many of the harshest federal criminal-sentencing laws of the 1980s and ’90s, laws that drove the nation’s prison crisis in the first place. He can’t undo the damage these federal laws have inflicted, but he can begin to repair it, and his own legacy on this issue, by reforming the pardon power from the ground up.