The just released Supreme Court decision on bump stocks, i.e., 22-976 Garland v Cargill, has resulted in a lot of politically charged and deceptive press releases, comments, and tweets by various people. But it really is simple to understand. The 1934 National Firearms Act (NFA, or The Act) narrowly defined "machine guns", aka fully automatic weapons. Under the Trump administration in the aftermath of the Las Vegas massacre, President Trump asked the Bureau of Alcohol, Tobacco, and Firearms to figure out a way to regulate bump stocks under The Act. Simply put, The Act was too narrowly written to allow this. Even the late Senator Feinstein agreed and was referenced in the majority opinion as saying it would take an act of Congress. Bottom line? It is up to Congress to amend the NFA if it wishes to cover these devices. That is actually what Justice Alito suggested in his concurrence.
As far as why this came about? The NFA explicitly said that an automatic
weapon was "...any weapon, which shoots, or is designed to shoot,
automatically or semi-automatically, more than one shot, without manual
reloading, by a single function of the trigger". A semiautomatic rifle, meanwhile, “requires a separate pull of the trigger to fire each cartridge.” For almost a century,
this definition has been accepted as applying to machine guns, i.e,
those guns which when the trigger is depressed and held down, the gun
continues to fire until the gun runs out of ammunition or the trigger is
released. A current example is a Glock pistol equipped with a "Glock Switch", basically an auto-sear. But in the case of a bump stock, the trigger is pressed and
released for each individual shot. What the bump stock does is harness
the energy of the recoil, coupled with pushing the gun forward, to
hasten the process of trigger pull and "trigger reset" by careful
manipulation. Simply put, bump stocks do not meet the definition in The
Act as machine guns. Bump stocks are more accurately called "trigger
accelerators" in that they are a class of devices that speed up the
semiautomatic action to simulate automatic fire. They do not, as a
matter of technical definition, legally meet the definition of a machine
gun.
The Supreme Court did not endorse bump stocks in its ruling. The Court
said that these attachments, i.e., trigger accelerators, fall outside the existing law
and that the law needed amending by Congress if they are to be covered. This really was a
separation of powers case. Call bump stocks a loophole, sure. The Court
said that the Executive Branch cannot re-write the law to close a
loophole where the law was so narrowly written. Clearly, reading the
U.S. Constitution, amending Federal law falls exclusively within the
role of Congress. An executive agency that reports to the President
cannot re-write Federal law. (and for those who disagree, imagine giving
a future President Trump this power.)
One can make the argument that bump stocks and similar devices definitely violate the spirit of the law, i.e., the clear intent of The Act, but that the 1934 Congress did not foresee these work-arounds. I agree with that perspective. But the Court chose to rule on what The Act said, not what could be interpreted. And I go back to my last comment in the previous paragraph about giving the Executive Branch too much leash.
As far as a Second Amendment argument, which was not even relevant in this case, the Supreme Court, in U.S. v Miller, noted that unless a weapon "...has some reasonable relationship to the preservation or efficiency of a well regulated militia, we cannot say that the Second Amendment guarantees the right to keep and bear such an instrument...". I note that no U.S forces or reserves have now or ever used bump stocks. Further, they make shooting wildly inaccurate (recall the Las Vegas shooter was randomly spraying bullets at a whole field of people, not an individual target), hence bump stocks are not likely useful for personal defense. So while they may be fun as an amusement attachment, they are not likely protected. And given the potential for mayhem and the legislative hazards of moving the legal goalposts of Federal law with work-arounds, bumpstocks are not worth fighting over. At least in my opinion.
In 2017 in the aftermath of the Las Vegas mass shooting where a killer
armed with bump stock equipped semiautomatic rifles massacred scores of
people, even the National Rifle Association and prominent Republicans
called for these devices to be regulated. But it was far easier to punt
the job to a Federal agency than for GOP members to answer to their
constituents for their support of a gun control law. Hence, in this and any other contentious issue, we increasingly govern by executive order or creative rule making. That's what needs
to change. Members of Congress have to put their votes where their
mouths are, so Congress has to do its job again. The U.S. is supposed to be governed by a triad: legislative, judicial, and executive. We've sawn off one leg.