[Tom Servo]

Most of the existing gun laws are patently unconstitutional, with the possible exception of some of the NFA stuff, as it is tax based, and you might be able to argue for it, although it is a stretch.

Actually, the NFA is a really good example of how the Commerce Clause can be used to stifle States' rights.

To quote John Ross:

A clear example of the fact that the National Firearms Act had nothing to do with crime and everything to do with government power occurred immediately prior to its passage. Senator Hatton Sumners of Texas, the Chairman of the House Judiciary Committee, had been a virulent opponent of the proposed bill and had bottled it up because it “did violence to states’ rights”

By Mr. Ross' estimates, compliance with the NFA registry was less than 1%, which isn't really surprising. Anyone supporting the NFA at the time would have been conscious of several factors:

1. Most folks in 1934 could not afford a $200 tax
2. The NFA wasn't highly publicized, and most people didn't even know about it
3. Even if it were a success, maintaing the infrastructure to administer a tax on millions of guns would have been unweildy and unprofitable

Plainly put, the NFA was a ban dressed up as a revenue-collecting measure, and FDR knew it.

US v. Miller was the big test, and unfortunately, we were in the Hugo Black period, after which the Supreme Court had abandoned any pretense of opposing FDR. If Miller had gone before the Court one year earlier, the NFA may very well have been declared unconstitutional, as it had been on the appellate level.

When Miller first went up for appeal in Arkansas, Circuit Judge Ragon ruled that, "the National Firearms Act is not a revenue measure but an attempt to usurp police power reserved to the States."

When it went before the Supreme Court (two months later), one of Barry's arguments in favor of the NFA was that the Treasury had jurisdiction because the shotgun had been transported across state lines. Never mind that there was no "commerce" involved. Guns or wheat: the Feds had a mandate to regulate whatever they wanted.

Federal laws on what guns can and cannot be imported are probably constitutional, as the feds have a lot of power in this area.

I'd disagree, but I tend to favor a very strict reading of Enumerated Powers. It'd certainly be a hard thing to fight, though.