It’s going to be illuminating to see whether the defense calls Vice President Biden in the case of the shotgun shooting of the teenaged thief. The case is the subject of a riveting dispatch in the New York Times. It involves the killing of a foreign exchange student named Diren Dede, who was in the process of trying to rob the home-garage of a resident of Missoula, Montana, when a motion sensor awoke the owner, Markus Kaarma, who got his shotgun and fired four cartridges into the garage, killing the hapless youth.

We are happy to leave it to the courts of Montana to try the facts in the case. We are struck, though, by echoes — not mentioned by the Times — of Vice President Biden. It was Mr. Biden who, in the gun debate that followed the Newtown, Connecticut, tragedy, urged people to get a shotgun. “If you want to protect yourself, get a double-barrel shotgun,” he said. He allowed that he told his wife, Jill, an educator, that if there’s ever a problem, she should go out on their balcony and “fire two blasts outside the house.”

That was too reckless for the more sober National Rifle Association (for one thing, it would leave Dr. Biden with an empty shotgun). And the two situations aren’t perfectly analogous. According to the Times, Mr. Kaarma fired his shotgun not outside the house but into the garage. He had, the Times reports, been troubled by burglars before. Mr. Kaarma may be able to cite Montana’s recent “castle-doctrine” law, which gives persons like Mr. Kaarma more discretion in defending their homes. It will be a learning moment.