There was a time, not so long ago, when teachers believed whipping unruly children was perfectly acceptable.

Parents often supported this outdated thinking, arguing that they'd endured the same punishments (or worse), and look how well they'd turned out.

Today we recognize that approach for what it is: savage and cruel.

But an equally severe - and ultimately ineffective and unjust - mode of punishment continues to be administrators' go-to way to deal with misbehaving students: suspend them or expel them from school.

President Barack Obama issued guidelines in 2014 advising school officials to avoid such exclusionary punishments, in large part because they fall most heavily on the shoulders of black and other minority students.

The guidelines urged educators to lessen their dependence on harsh penalties in favor of positive behavior interventions, such as counseling.

It was the right move. But perhaps not in the eyes of President Donald Trump, who never met an Obama-era policy he didn't try to shred.

Now the top law-enforcement official in New Jersey is calling on the Trump Administration to uphold those more compassionate, more equitable guidelines.

With his counterparts in nine other states and the District of Columbia, Attorney General Gurbir Grewal has reached out to U.S. Secretary of Education Betsy DeVos and U.S. Attorney General Jeff Sessions.

"While unnecessary exclusionary school discipline harms all students," the officials said in a letter last month, "it has a profoundly disproportionate effect based on race, disability and gender, as well as sexual orientation and identity."

The letter cited sobering findings by the Government Accountability Office: Black children account for about 16 percent of students in the country, but about 39 percent of students suspended from school.

A study in 2016 indicated that black students are three times more likely to be suspended from school, and nearly twice as likely to be expelled, than their white peers.

"Black students, particularly black boys, are looked at as deviant and defiant, while white students are seen as exploring and testing boundaries," said Tynisha Jointer, a behavioral health specialist for elementary schools in Chicago.

When we expel large segments of the population, we're essentially giving up on their futures. These students are less likely to graduate from high school, and more likely to get into trouble with the law.

While some advocates of the rollback fear that tying the hands of local educators makes it harder to remove disruptive or even dangerous students from the classroom, we believe expulsion should be the absolute last resort when all other interventions have failed.

There's no word yet which way the feds will move as the new school year gets under way. But we hope they take the AGs' letter to heart.

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