Most Americans probably never heard of a bump stock until the October 2017 shooting at a country music festival in Las Vegas where fifty-eight people were killed, and scores more injured, when a gunman using a bump stock fired down at a crowd from the window of a hotel.

Even fewer Americans have ever heard of Clark Aposhian—the only man in America who can legally own a bump stock.

A bump stock enables semi-automatic rifles to fire more rapidly. Early bump stocks were effectively outlawed by the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) in 2006. Modern bump stocks were perfectly legal at the time of the Las Vegas shooting. A bill was afterward introduced in Congress to ban bump stocks but it was never acted on.

Four months later, after the shooting at the Marjory Stoneman Douglas High School in Florida (a shooting where a bump stock was not used), President Trump asked the Department of Justice (DOJ) to prohibit bump stocks. In December of last year, the DOJ issued its final regulation to modify the definition in the ATF's rules of "machine guns" outlawed by Congress so that it included bump stocks. Owners of bump stocks were given three months to destroy or surrender to the ATF their bump stocks or face 10 years in prison and a $250,000 fine. There are supposedly 280,000 to 500,000 of the devices in the hands of Americans.

Gun Owners of America (GOA), the most hardcore and most consistent pro-gun organization in the United States, immediately challenged the bump stock ban in the U.S. District Court of Western Michigan. Last month, the District Court denied GOA's request for a preliminary injunction against the ban, as did the Sixth Circuit Court of Appeals. The U.S. Supreme Court has, for now, refused to stop the DOJ from enforcing its bump stock ban.

Aposhian, the chairman of the Utah Shooting Sports Council, added a bump stock to his firearms collection about a year before the Las Vegas shooting. He is the only man in the United States who can legally own one because of an exception granted exclusively to him "via an order from the 10th U.S. Circuit Court of Appeals that granted a temporary exemption to a Justice Department ban following the massacre."

Aposhian and his lawyers argue that the bump stock ban is unconstitutional because of how it was imposed. According to Mark Chenoweth, executive director of the New Civil Liberties Alliance, which is representing Aposhian:

If the courts allow the executive branch to color outside the lines in this way, you can be guaranteed they'll do it in the future, regardless of the context.

This is Congress's job to do. If you're going to change the law, it is absolutely and specifically the purview of Congress and our representatives, not the role of the president, not via executive order, let alone by an executive agency, to do this.

There is just one problem. Even if it was Congress that passed legislation banning bump stocks, it would still be unconstitutional, and for two reasons. One, the articles of the Constitution, and two, the Second Amendment of the Constitution.