The obvious solution isn't a viable one because it'd require all of the states to get on board with it and that's just not going to happen.Guns on the street are far more complex, but once you establish a choke point up stream, it will slow down the circulation of illicit firearms
What would be your solution?
You're not going to be able to enforce it when some of these states even require you to be licensed to purchase or carry guns.
You should fix the guns laws first before you add in the mental health check requirement for it.