The Hitler claim is fairly straightforward. For about 20 years, NRA mouthpiece Wayne LaPierre has been claiming that "In Germany, Jewish extermination began with the the Nazi Weapon Act of 1938, signed by Adolf Hitler." The idea idea is simple: a totalitarian government restricted gun ownership; ergo, any government that restricts gun ownership is totalitarian.
There are two things that must be said about this story.
First, it calls for an immediate application of Godwin's Rule, which says that as any online discussion [or here, we might say "heated argument among people uninhibited by either facts or mutual respect," which is the same thing] grows longer, the probability of a comparison to Nazis grows stronger. In other words, unless there is a grownup in the room, somebody will always wind up saying "Your side is just like Hitler, nanny-nanny-foo-foo."
Now, that doesn't mean the accusation is always wrong. If you're arguing against, say, somebody who wants to kill Jews, gypsies and gay people, then the comparison is pretty damned apt. But it does mean that, for the most part, dubious comparisons to the Third Reich are an inevitable component of public discourse in our morally and intellectually debased society, and that therefore they should be taken with a massive grain of salt.
The second thing, though, is this: the claims made about the Nazis and gun control are demonstrably false. In fact, the control of personal firearms was much tighter under Weimar than under the Reich. (Read an excellent article in Salon here; scholarly details here). Private weapons had been banned and confiscated after World War I; later, they were permitted, but permits were required to own, sell or carry them. The effect of Hitler's law was to overthrow this fairly strict regime, and to deregulate long guns, ease handgun restrictions, lower the age limits, and lengthen permits.
Basically, Hitler gave people access to more guns -- at least as long as those people were not Jews.
There remains, of course, the argument that if the Jews had enjoyed the same gun-ownership rights that other German citizens did, they would have been able to defend themselves against the Holocaust. This is specious. As Salon says:
Proponents of the theory sometimes point to the 1943 Warsaw Ghetto Uprising as evidence that, as Fox News’ Judge Andrew Napolitano put it, “those able to hold onto their arms and their basic right to self-defense were much more successful in resisting the Nazi genocide.” But as the Tablet’s Michael Moynihan points out, Napolitano’s history (curiously based on a citation of work by French Holocaust denier Robert Faurisson) is a bit off. In reality, only about 20 Germans were killed, while some 13,000 Jews were massacred. The remaining 50,000 who survived were promptly sent off to concentration camps.So, yeah, the Hitler story is a load of malarkey.
In any case, let's be clear about what the pro-gun extremists are really proposing. They envision taking up arms against a democratically-elected government because they do not approve of its policies. This is not even secession, a movement against which the nation has already defended itself decisively. No, there is another name for what these people are proposing: domestic terrorism.