In the weeks after Representative Charlie Dent signed on to legislation that would have banned bump stocks following the massacre in Las Vegas, the moderate Pennsylvania Republican was “besieged” by responses from his constituents. These were not thank-you calls. The vast majority of people contacting Dent were angry that he had endorsed even a modest restriction on the use of guns, he told me in a phone interview on Monday, a day after a man identified by police as Devin Kelley killed 26 men, women, and young children at a church in Sutherland Springs, Texas. It was the third mass shooting in the last 18 months in which more than two dozen people were killed. The bipartisan bill Dent co-sponsored would not have banned assault weapons or restricted the sale of guns to anyone, nor would it have expanded the use of background checks. The legislation would merely have outlawed a device that allows a gun to fire at a much higher rate of speed—to, in the description of the National Rifle Association, “allow semi-automatic rifles to function like fully automatic rifles.” A bump stock was what helped Stephen Paddock mow down hundreds of concert-goers from his elevated perch in the Mandalay Bay Resort and Casino on October 1, killing 59 of them. In the days that followed, everyone from Democrats to top Republicans to even the NRA came out in favor of more tightly regulating bump stocks, if not banning them entirely. But in the month since, Congress has taken no action on bump stocks or any other gun-related matter. The committees with jurisdiction have held no public hearings. Following the NRA’s lead, Republicans called on the Department of Alcohol, Tobacco, Firearms, and Explosives to look into bump stocks rather than tackle the issue themselves. In short, nothing much has happened, and the feedback that Charlie Dent received helps explain why. Polls have consistently shown broad public backing for additional regulations on guns, including more than 90 percent support for universal background checks. But, as Dent told me, “one side has historically been more energized.” And while advocates for gun control often focus on the millions of dollars that the NRA spends on