TALLAHASSEE — Citing gun restrictions dating back to the 1800s, a federal appeals court on Thursday upheld a 2018 Florida law that prevents sales of rifles and other long guns to people under age 21.

The law, passed in the aftermath of the mass shooting at Parkland’s Marjory Stoneman Douglas High School, is one of the only firearm restrictions approved by the Legislature in decades. Federal law already prohibits selling handguns to people under 21.

Lawmakers passed the measure weeks after Nikolas Cruz, who was 19 at the time, used an AR-15 rifle to kill 17 students and staff members and injure 17 others at the Broward County school.

The National Rifle Association quickly filed a federal lawsuit, arguing in part that the law imposes an unconstitutional restriction on the Second Amendment rights of people under 21.

Chief U.S. District Judge Mark Walker rejected the challenge in 2021, ruling that previous court opinions have given states leeway to impose Second Amendment restrictions in some instances. The NRA appealed, and a three-judge panel of the 11th U.S. Circuit Court of Appeals heard arguments last year.

The ruling came days after two Republican House members filed a bill (HB 1543) that would allow residents 18 or older to buy rifles, which was the law before the change.

Thursday’s decision relied heavily on guidance from a 2022 U.S. Supreme Court opinion in a case known as New York State Rifle & Pistol Association v. Bruen, which said gun laws must be “consistent with this nation’s historical tradition of firearm regulation.”

The history shows Florida’s 2018 law is consistent with such tradition, Judge Robin Rosenbaum wrote in an opinion joined fully by Judge Anne Conway. Judge Charles Wilson wrote a short concurring opinion.

The ruling mapped out the historical record on age restrictions. It also said the Florida law allows people under 21 to possess or use guns, such as guns that they receive as gifts.

In the mid-1800s, Rosenbaum wrote, Alabama and Tennessee laws prohibited selling, loaning or giving guns to people under 21, which was the age of majority in both states at the time. A similar law passed by Kentucky in 1859 included an exception allowing parents to give deadly weapons to their children.

The NRA “is currently assessing our appeal options” and is disappointed in Thursday’s decision, spokeswoman Amy Hunter said in an email.

“The NRA supports the right of law-abiding adults to possess firearms for self-defense, hunting and sport shooting. There is no reason why an adult who is old enough to defend his or her country should be restricted from exercising their Second Amendment rights,” Hunter said. “The NRA also looks forward to the Florida Legislature addressing the issue and removing this unconstitutional ban.”

The NRA has argued, in part, that the age restriction infringes on Second Amendment rights of young adults who have been authorized to use weapons when they serve in the military or in law enforcement.

The panel of the Atlanta-based appeals court disagreed with the NRA’s arguments related to people under 21 being able to use guns in the military or in law enforcement.

“The NRA’s conclusion is incorrect. The NRA mistakes a legal obligation for a right,” Rosenbaum wrote.