Contrary to what Collins et al. seem to think, the “assault weapon” category has no reality independent of legislation. “Assault weapons” are whatever legislators say they are. Hence the rifle used in the Newtown massacre was not an assault weapon when the crime was committed but became one after Connecticut legislators approved a new, broader definition of the term. Similarly, the rifles used by the perpetrators of the San Bernardino attack are not assault weapons unless and until the California legislature decides to call them that.

The Times, which says “certain kinds of weapons…must be outlawed for civilian ownership”—by which it means not only that future sales should be banned but that current owners should be forced to “give them up”—is confident “it is possible to define those guns in a clear and effective way.” But it does not propose a definition, presumably because such an exercise would make it obvious that the “assault weapon” label hinges on features, such as folding stocks, pistol grips, barrel shrouds, and flash suppressors, that make little or no difference in the hands of mass shooters or ordinary criminals, who in any case overwhelmingly prefer other types of guns.

In a 2014 essay titled “The Assault Weapon Myth,” ProPublica reporter Lois Becket noted that these demonized guns are a “politically defined category” based on scary looks rather than criminal significance. “The law that barred the sale of assault weapons from 1994 to 2004 made little difference,” she wrote. “It turns out that big, scary military rifles don’t kill the vast majority of the 11,000 Americans murdered with guns each year. Little handguns do.” Apparently the editors of the Times missed that essay, even though they published it. I guess they also missed the paper’s own coverage of this issue, which has intermittently explained how arbitrary the definition of “assault weapon” is and noted that AR-15-style rifles like those used by the San Bernardino murderers are among the most popular guns in the United States.