MADISON, Wis. — A Wisconsin judge wasn’t required to tell a man he would face a lifetime of GPS monitoring upon pleading guilty to child sex crimes because such monitoring is a public safety measure, not a form of punishment, the state Supreme Court ruled today.

The court concluded in a rare 7-0 decision that monitoring is designed to protect the public rather than punish the offender further.

“[Lifetime monitoring] provides a middle ground between releasing dangerous sex offenders into the public wholly unsupervised and civil commitment,” Justice Michael Gableman wrote in the ruling.

“In light of the ‘frightening and high’ rate of recidivism for sex offenders, the relatively minimal intrusion of lifetime GPS tracking … is not excessive in relation to protecting the public,” he wrote.

Wisconsin enacted a law in 2006 that requires serious child sex offenders and people deemed sexually violent to submit to lifetime GPS tracking by wearing ankle transmitters when they complete their sentences.

Tampering with the transmitters is a felony. The law allows offenders to petition to have tracking terminated after 20 years and allows the Department of Corrections to end it if the offender becomes incapacitated. Tracking also ends if the offender decides to move out of state.

The case the court ruled on involves DeAnthony Muldrow. The Manitowoc man pleaded guilty in 2010 to second-degree sexual assault of a child and third-degree sexual assault. He was sentenced to a year in prison, a year on extended supervision and probation. He’ll be subject to lifetime monitoring when his probation ends in 2022.

Muldrow sought to withdraw his guilty plea in 2015 because no one told him he would face lifetime GPS monitoring. He argued that he wasn’t told of a form a punishment he would face, which made his plea uninformed and a violation of his due process rights.

Manitowoc County Circuit Judge Jerome Fox denied the motion and the 2nd District Court of Appeals upheld Fox’s decision last year.

The appellate court acknowledged that lifetime monitoring imposes a burden and is an intrusive invasion of privacy that can result in embarrassment or worse. But those implications don’t make the requirement punitive, the court said.

The state Supreme Court agreed.

Gableman wrote that Wisconsin’s tracking statutes are included in a chapter that deals with Department of Corrections regulations rather than in the criminal punishments section. The department regulatory chapter opens with a statement saying the statutes are designed to facilitate rehabilitation, Gableman noted.

He wrote that the pathways for terminating tracking are tailored to ensure that offenders are tracked only when they pose a threat to state residents, not to punish them.

The ankle transmitters don’t confine offenders, Gableman added. He acknowledged that offenders must spend an hour a day next to a wall outlet to recharge the devices, but he argued that this is a minor restraint that doesn’t rise to punishment.

Since monitoring isn’t a punishment, it’s not a direct consequence of a guilty plea and therefore judges don’t need to tell defendants about it, Gableman concluded.

Muldrow’s attorney, Leonard Kachinsky, said he was disappointed but not surprised, given the state appellate ruling. He said he hopes judges and defense attorneys choose to inform defendants.

“Even though it may not be mandatory, it’s only fair warning that they know about the program,” he said.