Firearms, ammunition, etc.; those manufactured and retained in State not subject to federal law. (HB69)

Can Virginia declare that? Doesn't congress and the Supreme Court determine what constitutes "interstate commerce"? I'd really like to know by what power we could do such a thing.

Congress has the right to regulate interstate commerce, not intrastate commerce. It really is that simple. This is Virginia invoking the 10th Amendment. Other states should follow suit, or the Republic will fall.

We don't get to "invoke" an amendment. That's not how they work. The Supreme Court has a long series of opinions that have established what is and is not interstate commerce, all based on Article I, Section 8, Clause 3, aka the "commerce clause." The tenth amendment holds that powers that aren't delegated to the federal government are reserved by the states. The commerce clause gives the federal government the right to oversee commerce, and the Supreme Court has held repeatedly that the tenth amendment does not restrict that in any way.

In U.S. v. Sprague they wrote that the tenth amendment "added nothing" to the constitution." Wickardv. Filburn held that a man growing feed for his own chickens was subject to regulation under the commerce clause.

If you don't like seeing commerce within the state subject to regulation by the federal government, that's swell—you should push for an amendment to the constitution. But passing a law saying "we're not bound to adhere to the constitution" is not a law at all. It's a joke. You might as well pass a law in your house saying that you're not subject to state or local laws. You're welcome to do that, but it'd be a strong sign that all is not well with your sanity. :)

This isn't interstate commerce, waldo. several other states have already passed the similar legislation

I'm not giving you my opinion, I'm giving you the Supreme Court's opinion. But I'm sure it would be useful for everybody to find out more about these other states, and how they passed such bills. Could you provide some links to document your claim?

Waldo, this is "intrastate" commerce, not "interstate" commerce. This same state legislation has actually passed in Montana and is currently also up for votes in New Hampshire and Texas. There is precedent for this.

I'm very well aware of the difference, Phil, but the Supreme Court has repeatedly made clear that any commerce is interstate commerce. This goes back to Gibbens v. Ogden, in 1824, when the SCOTUS held in a unanimous ruling that when one state's intrastate commerce regulations infringe on another state's intrastate commerce, that is within Congress’ purview to take action. Justice William Johnson, writing in his concurrence, said of the framers’ intent:

If there was any one object riding over every other in the adoption of the constitution, it was to keep the commercial intercourse among the states free from all invidious and partial restraints.

The court briefly backtracked in Hammer v. Dagenhart (1918), which was a result of Congress’ prohibition on child labor. The plaintiff argued that Congress had no power to say whether or not children could be employed in factories, since that's a matter for the states to regulate.

But that split (5-4) ruling didn't last long—it was overturned in U.S. v. Darby Lumber Company in 1941. A lower court, relying on the Hammer ruling, found that the Fair Labor Standards Act was unenforceable within states (remembering that the Hammer precedent found that only interstate commerce could be regulated by Congress). But it was appealed up to the Supreme Court, who unanimously ruled that the Tenth Amendment is simply without power, and utterly rebuked Hammer. Writing for the majority (or, in other words, everybody on the court), Chief Justice Harlan Stone wrote:

In the more than a century which has elapsed since the decision of Gibbons v. Ogden, these principles of constitutional interpretation have been so long and repeatedly recognized by this Court as applicable to the Commerce Clause that there would be little occasion for repeating them now were it not for the decision of this Court twenty-two years ago in Hammer v. Dagenhart, 247 U.S. 251. In that case, it was held by a bare majority of the Court, over the powerful and now classic dissent of Mr. Justice Holmes setting forth the fundamental issues involved, [p116] that Congress was without power to exclude the products of child labor from interstate commerce. The reasoning and conclusion of the Court's opinion there cannot be reconciled with the conclusion which we have reached, that the power of Congress under the Commerce Clause is plenary to exclude any article from interstate commerce subject only to the specific prohibitions of the Constitution.

And, the coup de grace of this ruling:

The amendment states but a truism that all is retained which has not been surrendered. There is nothing in the history of its adoption to suggest that it was more than declaratory of the relationship between the national and state governments as it had been established by the Constitution before the amendment, or that its purpose was other than to allay fears that the new national government might seek to exercise powers not granted, and that the states might not be able to exercise fully their reserved powers.

There's no wiggle room there; it's unusually direct language for a SCOTUS ruling. And that stands as the law of the land which, as you can see, makes this bill completely impossible.

It's nice that this legislation has passed in Montana, but that doesn't mean anything. The legislature could pass a law barring white people from owning land, prohibiting firearm ownership, or abolishing newspapers, but lacking any legal merit, those laws would just be words on a page.