And that was why many Framers argued against a Bill of Rights.
The 21st Amendment to the Constitution sort of made buying liquor pursuant to State Law a Constitutional right. And for better or worse (mostly the latter!) that's how the right to bear arms has been treated (despite the obvious meaning of the Second Amendment).
ML/NJ
Oregon state law doesn't prohibit 18-20 year olds from purchasing long guns.
Oregon state law does prohibit 18-20 year olds from purchasing alcohol.
So getting back to your original question "What would happen if he tried this against a Liquor Store?", the two cases aren't the same.
In one, the seller is following state law, and in the other the seller is not.
And that was why many Framers argued against a Bill of Rights.
Yes. THis was one of the big discussions surrounding the adoption of the first 12 amendments to the Constitution (12 proposed 10 accepted initially) The Anti-Federalists argued that without the specific things outlined in the proposed Amendments, the governemnt would claim jurisdiction over those items. The Federalists claimed that by adding the specific rights protected, the government would claim that other natural rights don't exist.
I think it should be clear to everyone that both sides would have likely been completely astounded at comments from "conservatives" saying there is no "right to privacy" because it wasn't spelled out in exactly those terms. I think it's obvious from context surrounding the 4th and 5th that a Privacy Right is a fundamental part of our system, or at least is supposed to be.
However it does bring home the point that the "Federal Farmers" were exactly correct to say that even though we can't list everything, there are a few things that we should call out specifically because they are that important.