We don’t need new gun laws – we should just enforce the ones already on the books. That’s the familiar refrain of gun rights advocates when faced with even modest proposals to improve public safety.

But current law didn’t keep Norman J. Strobel of Naples, a felon and domestic abuser, from getting the weapon he recently used to kill a man.

It's not yet known how Norman J. Strobel got the gun he used to shoot two men: one in Casco, who was injured, and a second at this Naples mobile home, who was killed. Strobel would have failed the required federal background check at a licensed firearms dealer – but a private sale would have allowed him to avoid such scrutiny. Gregory Rec/Staff Photographer

Because of his criminal history, Strobel would have failed the federal instant background check that licensed firearms dealers must carry out. In Maine, though, prohibited persons can opt for private sales, where no such scrutiny is required – and, unfortunately, it’s a loophole that neither voters nor lawmakers here seem inclined to close.

Investigators haven’t released details yet on what gun Strobel used last weekend, or how he got it. We do know that he had a gun: His ex-girlfriend, whom he had threatened to kill, told a judge in a September letter that Strobel had bought a 9 mm handgun in a private sale two years ago. It’s also clear that it was illegal for him to own a weapon, because of a record dating back decades in Rhode Island, including felony assault, sexual assault and domestic abuse.

Apparently bent on carrying out his threats to his ex, Strobel drove to her Casco cottage late Saturday. Finding her not at home, Strobel shot and seriously injured her daughter’s boyfriend. Then, authorities say, he killed the acquaintance with whom he’d been sharing a mobile home in Naples, before his own death there early Sunday in an exchange of gunfire with police.

We don’t know whether Strobel exploited the private-sale loophole to buy the gun used in the shootings. But it would be unrealistic to expect that he would have sought out federal scrutiny when buying a weapon, since it’s so easy in Maine to avoid it by acquiring firearms through private sellers. A study by supporters of Question 3, the statewide proposal to expand background checks, identified 3,000 guns listed for sale in Maine through Uncle Henry’s classified magazine and the Armslist.com website.

And though most of those buyers and sellers are law-abiding people, guns found at crime scenes in Maine and other states have been traced to private sales in Maine in which there were no background checks.

But Question 3 failed at the polls on Election Day. So did similar measures when the Legislature weighed them in the aftermath of the Newtown, Connecticut, school shootings – evidence that despite the harm that can be done when guns get in the wrong hands, Mainers aren’t willing to do what it takes to make it less likely for that to happen.