“This is common sense,” Democratic Senator Joe Manchin said today as he and Republican Senator Pat Toomey announced their proposal to subject gun sales online and at gun shows to background checks. In the politics of guns, common sense counts as a major breakthrough. The bipartisan deal might even be enough to help background-check legislation pass in Congress. If not, the long-term implications of the compromise are still important.

The deal would require background checks -- and sales records, which help law-enforcement agencies track crimes -- on many gun purchases that now escape scrutiny. While still exempting some private transactions, including those between family members, the compromise would drastically expand background checks, in particular by closing the gun-show loophole. If the proposal survives a gantlet this week in Congress, it may well save lives.

The deal may also set the stage for future success. Both Manchin, of West Virginia, and Toomey, of Pennsylvania, have “A” ratings on the National Rifle Association’s legislative report card. Their support for background checks represents a political divorce of sorts, separating American gun culture, which both senators champion, from the extremism that characterizes the NRA, the Gun Owners of America and other elements of the professional gun lobby.

The culture and practice of hunting and sportsmanship deserve protection. As polls show, few hunters or sport shooters object to expanded background checks or other sensible legislation. The real impediment to safer laws is the gun lobby, which advances its ideological passions and marketing agenda with appeals to fear.

The gun lobby’s pretension to speak for hunters and sportsmen has grown increasingly specious. The support of Manchin and Toomey for background checks highlights the distinction between gun culture on one hand and ideology on the other. It also could mark a meaningful step in the too-slow journey toward sensible regulation.

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