Clinton Ehrlich is a visiting researcher at Moscow State Institute of International Relations. As a law student, he spearheaded the exoneration of Sgt. Raymond Jennings.

Eleven years ago — while on leave from Iraq — Sgt. Raymond Jennings was arrested at gunpoint and accused of murdering 18-year-old Michelle O’Keefe. Jennings was convicted and appeared destined to die in prison, having been given a 40-years-to-life sentence. The California Supreme Court declined to review his conviction.

Then something amazing happened: The district attorney’s office in Los Angeles ordered Jennings to be released from prison last year after prosecutors expressed doubts about his guilt.

Jennings is the first person exonerated by Los Angeles’s Conviction Review Unit — a unit within the district attorney’s office that helps innocent people behind bars. The program follows the model of an initiative of the same name in Brooklyn that has freed 22 people since 2014 .

We expect the Justice Department to set the gold standard for ethics and professionalism by prosecutors, but here it lags behind local jurisdictions such as Los Angeles. The department has not established conviction-review units in the federal justice system, and this failure is an abdication of moral leadership that prevents state and county governments from taking the concept seriously.

Federal prosecutors have created one local unit in the District, but the other 92 U.S. attorneys continue to ignore the problem. They refuse to acknowledge that a prosecutor’s ethical obligation to seek justice does not end once a conviction is obtained.

Few people expect Attorney General Jeff Sessions to tackle this problem. As a prosecutor in Alabama, he showed little interest in helping victims of the criminal justice system, which is why many legal scholars and activists opposed his nomination. Now that Sessions is in charge of the Justice Department, the onus is on him to prove his critics wrong.

There is no better starting point for reform than addressing wrongful convictions. About 2,000 exonerated people have been freed from our nation’s prisons in the past three decades. Worse, the harder we look, the more we find: Almost eight times as many prisoners were exonerated in 2015 as in 1989.

People often imagine that this is a result of DNA testing. If that were true, convictions would be simple to overturn, and courts would be well equipped to handle the influx of claims from prisoners. Unfortunately, the overwhelming majority of exonerations are made on other grounds.

Wrongful-conviction cases require time-intensive investigations that courts are not configured to provide. Even when a legal-aid group steps in to help a convict, it must break through the torrent of habeas petitions already overwhelming judges, from complaints on procedural errors to poor living conditions.

Conviction-review units can move more quickly because of their narrower mandate. Applicants have no right to an explanation or appeal when their claims are denied, so the units do not get bogged down. This lets investigators focus their resources on the minority of cases that merit their attention.

Most important, the conviction-review process is non-adversarial. It creates an internal forum for prosecutors to seek the truth rather than mechanically defend every conviction. When the state admits its own mistakes, they can be addressed rapidly.

Prosecutors who resist the movement for conviction-review units are pretending that such mistakes never occur. Part of the problem is public denial. The number of wrongful convictions is so disturbing that many people try to rationalize the problem away with soothing myths: “It couldn’t happen to me”; “They were probably lowlifes anyway”; or “That’s what happens when you hang around the wrong people.”

The exoneration of Ray Jennings shatters those stereotypes. He is a devout Christian and father of five who risked his life for his country in Iraq. He was present at the scene of a murder only because he was moonlighting as a security guard while studying to become a U.S. marshal.

The Justice Department should finally establish federal conviction-review units. Doing so would send the long-overdue signal that prosecutors must take responsibility for correcting their offices’ mistakes. Equally important, it would reassure our nation that the new attorney general has a moral compass worthy of the power that comes with the office.