The day the ATF published its new rule on pistol stabilizing braces in the Federal Register, it was hit with at least two lawsuits while Republicans on Capitol Hill are launching their own offensive. 

The 98-page rule, which was staunchly opposed by over 90 percent of the more than 237,000 people who commented on it last year, doesn't outlaw braces outright but does deem almost any pistol fitted with one to be a short barreled rifle under the National Firearms Act that needs to be registered with the agency in the next 120 days. Legal alternatives include destroying, removing the brace, turning the gun over to the government for disposal, or making it into a rifle by fitting a longer barrel. 

No sooner had the digital ink dried on the rule, it was hit with a federal lawsuit filed in the Northern District of Texas. Filed by the pro-gun Firearms Policy Coalition along with two plaintiffs-- William Mock and Christopher Lewis-- who are braced pistol owners, Mock v. Garland, argues that the ATF and Department of Justice are violating both the Administrative Procedure Act and the U.S. Constitution.
 

"Federal agencies do not have the power to write new laws, and yet the ATF continues to attempt to expand its authority using the federal rulemaking process," Cody J. Wisniewski, FPC’s Senior Attorney for Constitutional Litigation, told Guns.com in an email. "This ‘rule’ is, in effect, a federal law that will transform millions of peaceable people into felons overnight simply for owning a firearm that has been lawful to own for decades. We won’t stand idly by while the ATF tramples the rights of millions of peaceable individuals."

A second federal suit brought by the Texas Public Policy Foundation, Watterson v. ATF, was also filed against the agency in the Eastern District of Texas. 

"The Department of Justice cannot rewrite federal statutes by bureaucratic diktat and decide to turn millions of law-abiding Americans into criminals guilty of a felony,” said TPPF Senior Attorney Autumn Hamit Patterson in a statement. "The Constitution gives Congress—not executive agencies—the legislative power to amend laws."

Meanwhile, in Washington...

On Tuesday, U.S. Senators Roger Marshall (R-Kan) and John Kennedy (R-LA) introduced the Stop Harassing Owners of Rifles Today (SHORT) Act, which will repeal some of the more archaic elements of the National Firearms Act, including its regulation of short-barreled rifles. Further, the lawmakers have cosponsored a Congressional Review Act resolution to prevent the ATF’s new rule from taking effect. 

"Finalization of this pistol brace rule represents the worst fears of gun owners across the country,” said Marshall in a statement emailed to Guns.com. "The SHORT Act will protect Americans from the anti-2nd Amendment gun registry that the ATF is abusing the National Firearms Act to create. This Congress, I challenge my colleagues in both chambers to make protecting Americans’ 2nd Amendment Rights a priority and sign onto this legislation that will stop the ATF’s pistol brace rule in its tracks."

Estimates of those impacted by the rule range from an extreme low of 1.4 million individuals affected (the ATF's figure) to as many as 40 million (data from the government's non-partisan Congressional Research Services). The ATF anticipates the cost to implement the rule is $266.9 million.