A maintenance worker checks jail cells in New York in 2015. (Brendan Mcdermid/Reuters)

Danielle Allen is a political theorist at Harvard University and a contributing columnist for The Post.

Here’s a thought experiment.

In September 1995, over the course of a single week, at the age of 15, my baby cousin, Michael, robbed four people at gunpoint in South Los Angeles and was himself shot in an attempted carjacking on the same block when that victim wrestled away his gun and shot him through the neck. Michael’s actions were terrible and shameful. Luckily, he was the only person physically injured.

To have to stand up in public and say that someone you love did these things is an experience no one wants.

Michael’s actions came out of the blue. This was his first arrest. He had no history of violence. He had no criminal record. Two years earlier, he had, though, received probation for the theft of a radio from the home of a neighbor for whom his mother was house-sitting; his mother had taken him to the police. Over the intervening period of time, Michael had begun to flirt with gangs. This relationship was crystallizing in that week of violence.

After his arrest, Michael’s mother wanted to bail him out. Michael asked her not to. He thought that if he were back on the streets, he would only get in more trouble.

How should a kid like Michael be sentenced? How, more generally, should we respond to wrongdoing? Here’s my challenge to you: In my thought experiment, you can’t answer “prison.”

Given that constraint, what punishment should Michael receive? Here are our goals: We want to respond to wrongdoing so as to ensure that victims are made whole, that society is made whole, and that the wrongdoer, too, becomes whole and, having paid recompense, is prepared to contribute productively to society.

Does your mind draw a blank? If so, you are like most of us, accustomed to a system that thinks incarceration is the only way to respond to wrongdoing.

In the United States, 70 percent of our criminal sanctions consist of incarceration. That’s why it’s all we can think of. But a world that operates without an extensive reliance on prison is not a utopia; it is only a plane ride away. In Germany, incarceration is used for 6 percent of sanctions; in the Netherlands, it’s 10 percent, according to a 2013 Vera Institute report comparing our criminal-justice system with theirs.

Germany and the Netherlands rely predominantly on fines, linked to the offender’s ability to pay, and “transactions” or community sanctions — for instance, work orders that benefit the community, or training orders, or a combination. Halfway houses connect residential oversight with supervised work opportunities, which can be connected to paying restitution to victims and the community. The penal systems are built around the principles of rehabilitation, re-socialization and “association.” This is the idea that a criminal sanction is more likely to result in a wrongdoer’s successful reentry to society if it works to strengthen, not damage, the wrongdoer’s positive connections to family and community.

In 1995, just after California passed its “three strikes and you’re out” law, just after the Clinton administration’s 1994 Violent Crime Control and Law Enforcement Act, Michael pleaded guilty and received a sentence of 12 years and eight months. He served 11 years, proudly fighting California wildfires for the final phase of his incarceration. At 29, three years after his release on parole and a painful struggle with reentry, Michael was shot and killed by the lover he’d met in prison. I tell his story in full in my recent book “Cuz.” It is a distinctively American tragedy.

Currently, two criminal-justice-reform strategies are moving through Congress. Last fall, Sens. Charles E. Grassley (R-Iowa) and Richard J. Durbin (D-Ill.) introduced the Sentencing Reform and Corrections Act. The act tackles the problem of mandatory minimums and seeks to “improve fairness in sentencing of low-level, nonviolent offenders,” so as to permit law enforcement to focus on “violent offenders, major drug traffickers and criminal masterminds.” This month, Sens. John Cornyn (R-Tex.) and Sheldon Whitehouse (D-R.I.), alongside Reps. Douglas A. Collins (R-Ga.) and Hakeem Jeffries (D-N.Y.), introduced a prison reform bill called the First Step Act. This bill would offer individualized recidivism-reduction plans to all people incarcerated in federal prisons, and increase access to vocational training and educational support, as well as substance-abuse and mental-health resources. The bill would also introduce halfway houses or home confinement for the final phase of incarceration.

These bills have wrongly been cast as competitors. If we are to undo mass incarceration, we have to envision viable alternatives to incarceration. By making halfway houses and rehabilitative strategies central to our sanctioning system, the First Step Act would help the American public see new possibilities. It could thereby lay the foundation for true transformation of sentencing.

Policymakers too often forget that three-quarters of their work should be winning the hearts and minds of the public. To win sustainable, unwavering, widespread support for meaningful sentencing reform, we have to show that strategies of rehabilitation and restorative justice work. Lawmakers should embrace the First Step Act as a necessary part of painting that new picture. The Sentencing Reform and Corrections Act would benefit from our collective ability to imagine alternatives to incarceration.