Op-Ed: Teenagers shouldn’t be able to buy assault weapons

A gunman entered a grocery store in Buffalo, N.Y., last month and fatally shot 10 people. Just 10 days later, a gunman entered an elementary school in Uvalde, Texas, and killed 19 students and two teachers.

These horrific tragedies have two things in common: teenage suspects were able to legally purchase AR-15-style assault weapons, and the shooters used such guns to kill as many people as possible, as quickly as possible.

Under current law, a firearms dealer with a federal license may not sell a handgun to a buyer under the age of 21. When that law was passed in 1968, it had broad bipartisan support in the House and the Senate.

However, this protection doesn’t apply to military-style assault weapons. The minimum age to buy an assault rifle is only 18. Simply put, this disparity costs lives.

If you can’t buy a six pack of beer or a pack of cigarettes, you shouldn’t be able to buy an assault weapon. It’s long past time that Congress addresses this incongruence.

That’s why we need the Age 21 Act, a bill to prohibit anyone under the age of 21 from purchasing assault weapons. President Biden announced his support for the bill, and I’m hopeful we can build bipartisan support for this common-sense measure.

I first joined this bill in 2018 when it was introduced by Republican Sen. Jeff Flake of Arizona after a teenage gunman killed 17 at Marjory Stoneman Douglas High School in Parkland, Fla. I reintroduced it last Congress, when perhaps it could have prevented the Buffalo and Uvalde shootings.

After the shooting in Buffalo, I introduced the bill again. It has no Republican co-sponsors in the Senate, but it does have broad public support. A recent poll by Politico showed 88% of Democrats and 68% of Republicans support a minimum age of 21 to purchase any firearm.

Assault weapons like the AR-15-style rifle have become the weapons of choice for mass shooters, including in most school shootings. And as we have seen, it’s all too common in recent history for shooters to be teenagers or young adults.

A New York Times analysis of mass shootings found that between 1949 and 2017, only two of the 30 deadliest shootings were committed by people under 21. Compare that with the last four years, when the gunman or suspect in six of the nine deadliest mass shootings was a man under the age of 21.

The Giffords Law Center, using FBI and census data, calculated that while 18- to 20-year-olds make up just 4% of the U.S. population, they commit 17% of all homicides. The Age 21 Act won’t stop young men in this age range from obtaining weapons. But it will make it harder for them to get the guns used to kill the most people.

Research illustrates why it’s so important to keep guns away from young people. Brain development extends well into the mid-20s, particularly development of areas of the brain used for judgment and impulse control. Too young to buy a handgun or alcohol — and too young to buy assault weapons.

There are dozens of gun safety bills before the House and Senate to address our epidemic of gun violence. These include proposals to outlaw hard-to-trace “ghost guns,” to support states in creating red-flag laws to identify threats, to prevent convicted domestic abusers from buying guns, and to ban silencers, assault weapons and high-capacity magazines. I support many of these measures.

But the Age 21 Act in particular would address the problem of school shootings, where so many young perpetrators are often current or recent students, and yet are able to legally obtain weapons of war.

We know from experience that if you limit access to assault weapons, mass shootings decrease. In 1994, I authored the Assault Weapons Ban. In the 10 years the ban was in place, gun massacres dropped 37%; after the ban expired in 2004, gun massacres rose 183%.

I believe the American people are mobilized and motivated to ensure that we pass common-sense gun reform and that should include raising the age to purchase an assault weapon.

Dianne Feinstein, a Democrat, is the senior U.S. senator from California.