Originally published in The Hill on April 5, 2019

Following the tragic mass shooting in Las Vegas on Oct. 1, 2017, where the assailant reportedly used firearms equipped with bump stocks, lawmakers in both parties attempted to restrict these devices legislatively, to require them to be registered or banning their sale. These efforts did not succeed, and President Donald Trump ordered ATF to take action.

Last week a formal bump stock ban went into effect for the majority of the country. The ban ordered anyone who lawfully purchased one of these devices to either surrender or destroy it, or else face felony prosecution.

Before the ban, the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) had recognized repeatedly that bump stocks are a lawful firearm accessory and not machineguns, because a user of a bump stock still must engage the trigger once for every shot fired. In a 2013 letter to Congress, ATF explained that bump stocks “are not subject to the provisions of Federal firearms statutes” and “ATF does not have the authority to restrict their lawful possession, use, or transfer.”

In a surreal bit of doublethink, ATF now insists that every bump stock previously sold was always a machinegun. So, not only are bump stocks now banned, but the agency claims it could always have prosecuted the owners of these devices — even though they were sold with ATF letters of approval attached.

To reach this absurd conclusion, ATF had to promulgate a bump stock rule that changed the statutory definition of “machinegun.” Under the new rule, a semiautomatic weapon is a machinegun if the shooter fires by bumping the trigger instead of “pulling” it. The new rule also defines “automatic” fire to include firing that requires “additional physical manipulation” of the weapon between shots, which used to be considered “manual” fire.

As soon as the final rule was promulgated, it was challenged in courts across the country, including by the organization I work for: the New Civil Liberties Alliance. In the first decision on these cases, a federal judge in Washington, D.C. denied a preliminary request to stop the final rule from taking effect. Relying on so-called Chevron deference, the court concluded that it “must accept an agency’s authoritative interpretation of an ambiguous statutory provision if the agency’s interpretation is reasonable.” This means that even though ATF’s interpretation was not the “best reading” of the statute, the court decided it had to accept it.

In other pending bump stock lawsuits, the government has said it has not and does not “contend… that the deference afforded under Chevron… applies in this action.” This concession comes because the government knows its reading of a criminal statute is not entitled to any deference.

The D.C. District Court ruled in ATF’s favor out of “deference” to its governmental role, even though it would result in making half a million law-abiding citizens into criminals.

This brazen abdication of judicial independence shows just how unlawful much of modern administrative activity is. Article I, Section 1 of the Constitution vests “all” legislative power in Congress. No part of the Constitution allows a law enforcement agency to rewrite a law it disagrees with, nor does it allow a federal court to sit idly by while that same agency prosecutes citizens for violating the new, made-up law.

This decision proved too much even for the famously agency-friendly U.S. Court of Appeals for the District of Columbia Circuit, which ordered ATF not to enforce the ban against the litigants in that case pending a full appeal.

Several court challenges to the bump stock rule continue. Even if courts refuse to apply Chevron deference, lawmakers may still get away with passing the buck to the Executive Branch on this difficult issue.

Caleb Kruckenberg is Litigation Counsel at the New Civil Liberties Alliance, which has filed legal challenges to the Bump Stock Final Rule that are currently pending in the Tenth Circuit and the Western District of Texas.