After the massacre, press secretary Jay Carney reiterated Obama's support for reinstating the federal "assault weapon" ban that expired in 2004, and Sen. Dianne Feinstein, D-Calif., promised to introduce a bill aimed at doing so next month. But we know for sure that an "assault weapon" ban would not have stopped Lanza or made his attack less deadly, because it didn't.
The rifle that Lanza used, a .223-caliber Bushmaster M4 carbine, is legal under Connecticut's "assault weapon" ban, and the federal law used the same criteria. Except for specifically listed models, both laws cover semi-automatic rifles with detachable magazines that have at least two of these five features: 1) a folding or telescoping stock, 2) a pistol grip, 3) a bayonet mount, 4) a grenade launcher and 5) a flash suppressor or threaded barrel.
The fact that such features have little or no functional significance in the context of violent crime reveals the folly of trying to distinguish between "good" and "bad" guns. Any gun that can be used for self-defense or other legitimate purposes also can be used to murder people.
Guns like Lanza's, modeled after the Colt AR-15, are among the most popular rifles in America, with an estimated 3.5 million sold since 1986. Only a tiny fraction of them are ever used in crimes.
Prior to the federal "assault weapon" ban, firearms covered by the law were used in something like 2 percent of gun crimes, and these were mostly pistols, according to a 2004 study sponsored by the National Institute of Justice. FBI numbers indicate that rifles of any kind (not just "assault weapons") are used in less than 3 percent of murders. Even killers with multiple victims are much more likely to use ordinary handguns than "assault weapons."
I use those scare quotes because the very term "assault weapon" was invented by the anti-gun lobby as a way of blurring the distinction between semi-automatic firearms, which fire once per trigger pull, and machine guns such as the selective-fire assault rifles carried by soldiers. The president himself either does not understand the difference or deliberately obscures it, calling upon Congress to ban "AK-47s" and "automatic weapons."