Under duress as in the legislature and the Governor were physically threatened with violence, or under duress as in Federal Highway funds would be withheld if it were not passed?
Let's hear the reasonable argument that constitutionally protects 18-20 year old's right to purchase alcohol. Notice I didn't say right to 'drink.'
Likewise, an 18-20 year old's right to possess a long gun or handgun would not change, only their ability to purchase a long gun.
What if the 20 year old lived in New York City?
The Constitution was written to establish what the Federal and State governments could and couldn't do; not to protect or grant rights to citizens. I doubt that very many people at the time of the adoption of the Constitution considered it unusual for an 18 year-old to buy a beer. Only the warehousing of children in public schools changed that.
ML/NJ