Discussion over at Sebastian's got me doing some research on something that's been on my mind for a while. The present ban on civilian purchases of new machine guns is very likely illegal, and I think there's actually a decent chance of overturning it in the courts.
It's commonly known that in the US, fully automatic firearms and short barreled rifles and shotguns are strictly regulated under the National Firearms Act of 1934, which imposes some heavy-duty licensing restrictions. Since back then people still respected the separation of powers, Congress knew it didn't have the authority to restrict gun ownership because that authority is left to the states under the Tenth Amendment. So the feds stretched tax laws until they got what they wanted: the extremely burdensome regulatory requirements were merely part of a system to collect a $200-per-gun "tax" on the weapons in question (a sum that, at the time, nearly doubled the cost of even the extremely expensive Thompson). This is precisely the same strategy used to outlaw marijuana (which is why alcohol prohibition, quite properly, required a constitutional amendment, while pot prohibition came down by mere legislative fiat).
Obviously, this is a serious misuse of tax codes. What good is a constitution that forbids the feds from banning a thing if they can just put a trillion dollar tax on it? Particularly when the restricted activity is specifically protected by the Bill of Rights--imagine a federal law that placed a $200 "tax" on blog posts critical of the government. It's disturbing and unacceptable, no matter what you may think of machine guns in particular (and in real life, they're much less dangerous to public safety than most people reasonably assume) So naturally, the NFA ended up being challenged in the Supreme Court. More than once, in fact. But the last word came down in United States v. Miller in 1939. Miller, who had been arrested for crossing state lines with an unregistered short-barreled shotgun, argued the obvious points.
Unfortunately, the Court upheld the NFA on two bases: first, that the Second Amendment specifically protects only the ownership of military weapons, and that there was an "absence of any evidence" that short-barreled shotguns were used by the military (in fact, they've been used in every US conflict since the Revolution, but as Miller was dead by the time the case was heard, no defense evidence was presented to the Court).
Second, the Court upheld a previous precedent that, in general, it wouldn't try to assess whether Congressional powers of taxation were being misused:
A duly interposed demurrer alleged: The National Firearms Act is not a revenue measure but an attempt to usurp police power reserved to the States, and is therefore unconstitutional.
Considering Sonzinsky v. United States, 1937…the objection that the Act usurps police power reserved to the States is plainly untenable.
Sonzinsky was an Illinois gun dealer convicted of failing to pay the "taxes" mandated under the NFA. From the ruling in that case (edited for brevity; the original is brimming with citations):
In the exercise of its constitutional power to lay taxes, Congress may select the subjects of taxation, choosing some and omitting others...Its power extends to the imposition of exercise taxes upon the doing of business...Petitioner does not deny that Congress may tax his business as a dealer in firearms. He insists that the present levy is not a true tax, but a penalty imposed for the purpose of suppressing traffic in a certain noxious type of firearms, the local regulation of which is reserved to the states because not granted to the national government...The cumulative effect on the distribution of a limited class of firearms, of relatively small value, by the successive imposition of different taxes...is said to be prohibitive in effect and to disclose unmistakably the legislative purpose to regulate rather than to tax.
Every tax is in some measure regulatory. To some extent it interposes an economic impediment to the activity taxed as compared with others not taxed. But a tax is not any the less a tax because it has a regulatory effect...and it has long been established that an Act of Congress which on its face purports to be an exercise of the taxing power is not any the less so because the tax is burdensome or tends to restrict or suppress the thing taxed.
Inquiry into the hidden motives which may move Congress to exercise a power constitutionally conferred upon…it is beyond the competency of courts...They will not undertake, by collateral inquiry as to the measure of the regulatory effect of a tax, to ascribe to Congress an attempt, under the guise of taxation, to exercise another power denied by the Federal Constitution.
Here the annual tax of $200 is productive of some revenue. We are not free to speculate as to the motives which moved Congress to impose it, or as to the extent to which it may operate to restrict the activities taxed. As it is not attended by an offensive regulation, and since it operates as a tax, it is within the national taxing power.
In short: if it could generate revenue, we don't wanna hear about it; Congress has the benefit of the doubt, period. A pretty disturbing stance for the Supreme Court to take, but they took it nonetheless.
Half a century later in 1986, in a bald-faced attempt to score points with the anti-gun lobby, representative William Hughes, a Democrat from New Jersey (go figure), used a middle-of-the-night unrecorded voice vote by a partial Congress to insert an amendment into the Firearms Owners Protection Act. The Hughes Amendment closed the NFA registry to new machine guns, freezing the supply of "transferable" fully automatic firearms to those already registered by 1986. The result of this has been to artificially drive prices well beyond the means of ordinary Americans. It isn't unusual for a firearm that should cost around $1,000 to sell for nearly $20,000.
Set before the Court again, we could demonstrate factually that neither of the principles on which Miller was decided remains valid. With the registry closed, the NFA restrictions on machine guns cannot be defended as a revenue-generating mechanism. And at least in the case of short-barreled arms and machine guns, we can very easily demonstrate that they're military weapons. Silencers (also "taxed" under the NFA) are probably still screwed.
This isn't all speculation. What I’m saying has already been argued, and won in federal court. It just hasn't been taken all the way to the Supremes yet. And that was in 1991, long before Heller, and in a legal and social environment much less friendly to gun rights than we have today.
Lots of smart folks out there think that we have to fix the NFA through Congress, not the judiciary, citing Heller's approval of restrictions on "dangerous and unusual weapons". But the combination of NFA and Hughes can be attacked without relying on Heller. Getting rid of the NFA is probably out for the forseeable future, but opening the registry seems fairly solid. If they can save the NFA by repealing Hughes, I'd expect Congress to repeal Hughes.