TALLAHASSEE — A federal appeals court next month will hear arguments in the National Rifle Association’s constitutional challenge to a Florida law that prevents people under age 21 from purchasing rifles and other long guns.

The 11th U.S. Circuit Court of Appeals last week scheduled an Oct. 22 hearing in Atlanta, as it considers a law that passed in the aftermath of the February 2018 mass shooting at Parkland’s Marjory Stoneman Douglas High School that killed 17 people.

A federal district judge and a three-judge panel of the appeals court upheld the age restriction, but the full appeals court last year decided to take up the case in what is known as an “en banc” hearing.

As the Florida lawsuit has played out, the U.S. Supreme Court has issued closely watched opinions in other gun-related cases. That has resulted in attorneys for Florida and the NRA debating how the Supreme Court opinions should apply to the dispute about the constitutionality of the age restriction.

The NRA argued in a July 31 brief that the Florida law did not align with a 2022 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.”

“This law is unconstitutional. The Second Amendment’s text protects young adults’ right to purchase a firearm, and the state has not proven that the ban is consistent with our nation’s historical tradition of firearm regulation. The young adult ban cannot stand,” John Parker Sweeney, an attorney with the Washington, D.C.-based Bradley Arant Boult Cummings LLP firm, wrote in the brief.

But in an Aug. 30 brief, the state’s attorneys contended that the law “fits neatly within” the nation’s “historical tradition.” While the law bars people under 21 from buying rifles and other long guns, they are able to get the guns, for example, as gifts from relatives.

“Florida’s law restricting the purchase, but not possession or use, of firearms by those under 21 is consistent with the principles that underpin our regulatory tradition. At the (nation’s) founding, individuals under 21 were considered lacking in the requisite judgment and reason to enter into contracts, which at the time were necessary to purchase firearms because such goods were bought on credit in early America’s agrarian economy. States recognized this common-law limitation when enacting their militia laws,” the state’s brief said.

The Republican-controlled Legislature and then-Gov. Rick Scott rushed to include the age restriction in a school-safety bill after Nikolas Cruz, who was 19 at the time, used a semiautomatic rifle in the Marjory Stoneman Douglas mass shooting. Federal law already prevented people under 21 from buying handguns.

The NRA quickly filed the lawsuit, alleging that the Florida age restriction violated Second Amendment rights.

While the full appeals court decided last year to take up the issue, the case was put on hold until after the Supreme Court issued a decision in a Texas gun case. The Supreme Court’s 8-1 decision in June in the Texas case backed a ban on gun possession by people under domestic-violence restraining orders and was a victory for the federal government and gun-control supporters.

Amid the Florida lawsuit, the state House in 2023 and 2024 approved bills to lower the minimum age from 21 to 18 to buy rifles and other long guns. The Senate, however, did not pass the measures, keeping the 2018 law in effect.