Former Arizona congresswoman Gabby Giffords, second from left, and Gov. Jay Inslee, left, fist bump at a rally in support of Initiative 1491 in Seattle last month. (Alan Berner/ASSOCIATED PRESS)

GUN CONTROL was a central tenet of Hillary Clinton’s unsuccessful campaign for president, but it would be wrong to interpret the results of the Nov. 8 elections as a slam dunk for those opposed to sensible gun laws. Three states approved ballot initiatives for strengthened gun-control measures despite stiff opposition from the national gun lobby. In statehouse races across the country, gun-control advocates had some success in helping to oust longtime gun-safety opponents. There should be no illusions about the difficulty that lies ahead in sustaining and furthering reform, but it is encouraging to see these signs of an increasingly robust grass-roots movement.

In a year that saw a record number of ballot initiatives, voters in Nevada, California and Washington state gave their approval to strengthened gun-safety measures while an effort in Maine to expand universal background checks failed narrowly. Nevada’s move to expand background checks to private gun sales and transfers was seen as particularly significant since the National Rifle Association invested heavily there with an aggressive campaign that included opposition from the governor and attorney general. According to Everytown for Gun Safety and Moms Demand Action, the win in Nevada means that nearly half of Americans will now live in states that have closed the background-check loophole. Eight states did so in the years that followed the slaughter of schoolchildren at Sandy Hook.

Other bright spots: Sen. Patrick J. Toomey (Pa.) showed that Republicans who support gun control can still win reelection while Sen. Kelly Ayotte (N.H.) proved that Republicans who oppose gun safety can lose. And in Oregon every elected leader up for election who voted “yes” on the state’s 2015 background-check bill won reelection. Of course, factors other than gun issues played a role in these elections, and the NRA, which spent a record $30 million, had its victories. But even its early and aggressive backing of Donald Trump was offset by the fact that the most aggressively pro-gun-control presidential candidate in history won the popular vote.

That, of course, is not likely to stop the gun lobby from wanting to cash in on its investment by pushing extreme measures such as repealing the federal gun-free school zone law, establishing national reciprocity for concealed-carry permits, gutting efforts to crack down on illegal gun trafficking and more. Gun laws in the District unfortunately will be particularly vulnerable. So let’s hope that the mettle that gun- control advocates have shown in recent years in stopping NRA-backed bills in statehouses will prove successful in meeting the coming challenges.