It’s a far easier lift to improve the background-check system than to revive a defective, widely reviled, and weak assault-weapons ban, but since Newtown, assault weapons are making the headlines. Vice President Joe Biden will unveil a sweeping gun-control agenda in late January that will include as marquee items an assault-weapons ban and limits on high-capacity ammunition. Closing background-check loopholes falls under the fine print.

But it shouldn’t. Current law requires licensed firearms dealers to run potential buyers’ names and Social Security numbers through the National Instant Criminal Background Check System, or NICS. The system works pretty well, and if gun shops were the only places where people could go to purchase guns, it would work even better.

Gun-control advocates and the White House want to institute background checks for private sales, most of which happen at gun shows, accounting for almost half of the country’s purchases. Interstate trafficking of guns generally is 48 percent lower in states where private gun sales are regulated, according to a 2009 Johns Hopkins study…

There is less disagreement about background checks than other gun-control issues, which means the administration may want to go for a larger bite of the apple. The most hard-core Republicans say that background checks are OK. Rep. Jim Jordan of Ohio, a tea party favorite, said he supports them for people seeking to carry a concealed weapon. Sen. Ted Cruz of Texas said he wants to strengthen NICS. Gun owners and dealers say that broadened background checks are a good idea. Still, neither Jordan nor Cruz has mentioned closing the gun-show loophole.