This was tried with Slavery, it was very popular with the two political parties, and it led to a civil war, whose conclusion was: no, states do not get to decide on slavery, and additionally they do not get to secede if they disagree with the federal government.

That being said, I don’t think any of these three particular things would become the underpinning of a society or an economy, to the extent that slavery was in the antebellum South. So, there probably wouldn’t be another Civil War fought over it.

I think the 2nd amendment one is the most interesting one to me, since our interpretation of it has become so distorted with the passage of time, and since we don’t seem to be converging over time on a consensus (unlike the other two, which were basically contrived for political purposes in the last generation). It’s almost impossible to imagine what the founding fathers would think about its application today.

From a US perspective, how would you deal with interstate commerce? Would the federal government be able to interfere as a result?

Would companies State A (where drugs are legal) be able to trade freely with citizens in State B (where drugs are illegal) without an inspection at the border? Would citizens from State B (where guns are legal) be able to travel freely to State A (where they are heavily restricted) without an inspection at the border?

What laws could State B (where abortion is illegal) create to punish its residents for travelling to State A (where abortions are legal) to get an abortion? How would this disparately impact people based on wealth (i.e someone who could freely afford to fly to State A, vs someone who lives on a min-wage job)

My understanding is that US states aren't able to pass extraterritorial laws or claim personal jurisdiction based on someone being normally resident within their state. That should prevent states from punishing residents for travelling to carry out acts which are legal at their destination.

Similarly it should be implicit from the existence and intent of the amendment that the Interstate Commerce Clause doesn't allow the federal government to render it null and void. I think it is a common legal principle that earlier, more general laws are overridden by later, more specific laws.

Finally, I don't think there is anything unique about this hypothetical amendment from the perspective of wealth inequality. There are plenty of things that wealthier people are able to take advantage of, including travelling to countries where the drinking age is lower, for example.

You'd have drug and gun smuggling between states, and abortion tourism between states.

So in practice there'd be little difference between what people do now and what they would do if this amendment was accepted.

What would change, however, is the temperature of debates about federal politics, and it would become harder for the two main parties to distinguish themselves and divide the population.