Not very imaginative, are you? Tell me, do you think that the ownership of living cannibus plants is protected from seizure? No, of course not. They have been declared "contraband." Tell me what happens if Congress passes and Obama signs a law stating that all magazine fed semi-automatic rifles of greater than .21 caliber are contraband, along with the magazines and any other accessories, since they are so dangerous. A compliant Supreme Court will say that such is a "reasonable regulation" (as mentioned in the Heller case), and therefore doesn't violate the 2nd Amendment. All that you need is 1 justice to change his mind, or to be "unavailable" to hear the case. "Change his mind" and "Unavailable" can occur many ways, and in countries that have previously banned weapons to the civilian populace, many strange things have happened to opponents of the regime.
In short, please don't be naive. Under our law you are, of course, correct. Just don't assume that things will necessarily stay the same.
Cannibus has been illegal since the 1930s. I think the marijuana prohibition survived at least one Supreme Court Challenge. Find a better example because there is no Constitutional provision to get high. Unless it is a prusuit of happiness thing.
An amendment was needed to prohibit alcohol. The only way an existing brewery or distiller could be shut down was with an amendment. The peculiar thing about Prohibition was that simple consumption was not outlawed.
One more thing - Liberal Democrats might be a little looney, but they ain’t that looney. Confiscation would possibly the thing that ends the Democratic party.