Last month the Obama administration imposed a rule that requires firearms retailers in Mexico border states to report semi-automatic rifle “bulk sales” (meaning more than one). Yesterday the N.R.A. funded a lawsuit challenging that federal regulation.

The Obama administration says that the law will stop gun smugglers, called “straw buyers,” from buying guns in the U.S. and then running them into Mexico to feed its ever waging drug war. But the N.R.A. sees it differently.

“[The] N.R.A. has always viewed this [regulation] as a blatant attempt by the Obama administration to pursue their gun control agenda through back-door rule-making, and the N.R.A. will fight them every step of the way,” Wayne LaPierre, the executive vice president of the NRA, told the New York Times.

Here’s what the current regulation dictates: Gun retailers in Arizona, California, New Mexico and Texas must report whenever someone buys more than one semi-automatic rifle that is larger than a .22 and is capable of using a detachable magazine. Not only do ARs fit into this category, but so do many popular sporting rifles like the Browning BAR and the Remington Woodsmaster. The report must be made to the federal government within five days. The Bureau of Alcohol, Tobacco, Fireams and Explosives would start enforcing this law on the 14th, according to the New York Times.

The lawsuit to stop the regulation is funded by the N.R.A. but it’s being brought by two large Arizona gun retailers. They say that reporting these sales would cost them business and violate the privacy of their customers. From a legal standpoint, the retailers and the NRA are arguing that the Obama administration overstepped its bounds by imposing this regulation without first getting the OK from Congress. Not to mention, they don’t think it will do anything to stop gun smugglers.

“This scheme will unjustly burden law-abiding retailers in these four border states. It will not affect drug cartels and it won’t prevent violence along our borders,” NRA Executive Director Chris Cox said. “It will only divert scarce law enforcement resources from legitimate criminal investigations and squander them on policing law-abiding retailers.”