During the last couple of years, Minnesota lawmakers wisely approved important, commonsense gun safety laws that were a long time in the making. The state now has what is known as a red-flag rule that allows family members and law enforcement to petition for an extreme risk protection order if someone with a firearm is believed to be a danger to themselves or others. And other gun control measures, including expanded background checks, are among hard-won changes in law.

Yet following that welcome progress, a recent federal appeals court ruling threatens to undo an older gun safety law that should remain on the books. Last week, a federal appeals court ruled that a Minnesota statute that since 2003 has banned 18- to 20-year-olds from carrying handguns publicly is unconstitutional. The Eighth Circuit of U.S. Court of Appeals agreed with a lower federal court.

In an interview with an editorial writer, Minnesota Attorney General Keith Ellison said that he’s still discussing the case with his team but is leaning heavily toward further appeal. That would be the right decision. The age restriction is an important public safety provision that’s worth fighting to preserve.

Ellison said Minnesota’s law doesn’t prevent that age group from having guns at all but that they can’t walk around with them casually.

He added that scientific research on brain development and judgment confirms why Minnesota’s restrictions should continue. There are such rules around buying cigarettes and liquor as well as driving; it’s reasonable to apply them to openly carrying deadly firearms. Ellison also pointed out that many of those involved in shootings with multiple victims are in that younger age group, including the 20-year-old who just days ago tried to take the life of Donald Trump.

The appeals court ruling was issued nearly three years after several gun-rights advocacy groups and three young adults sued Minnesota’s public safety commissioner and the sheriffs of several counties. They claimed that the age restrictions violated their Second Amendment rights.

Bryan Strawser, chair of the Minnesota Gun Owners Caucus, a plaintiff in the suit, said in a statement after the ruling that the decision was “a resounding victory for 18- to 20-year-old adults who wish to exercise their constitutional right to bear arms.”

Still, Minnesota is not alone in imposing this type of control. A total of 19 states and the District of Columbia filed an amicus brief with the Eighth Circuit in support of Minnesota in the case. In that brief, they stated that the Second Amendment allows states to “enact sensible and varied firearms regulations designed to protect the public,” according to information provided by Ellison’s office.

The brief went on to note that many states have imposed age-based regulations on the purchase, possession or use of firearms. It also said that though rules differ slightly by jurisdiction, more than 30 states and D.C. have established a minimum age requirement of 21 for individuals to publicly carry certain types of guns.

As the Star Tribune Editorial Board has previously stated, the attorney general was right to pursue the first appeal last year. The state should challenge the more recent decision and continue to fight to maintain Minnesota’s conceal-carry age restriction.