If Obamacare survives, they’ll do it through medical insurance. They’ll require doctors to ask questions about gun ownership and whether the patient has ever had an unkind thought about a minority, Globull Warming, etc.
One wrong answer and Presto! you’re not mentally competent to possess a firearm. The supreme court will aprove it.
On a related note, my internist has told me to drink one glass of red wine a day as it keeps the platelets from adhering, according to some studies. Wait till the lefties and the nosy get into the business of regulating guns. I can see the questions: Do you own or have access to a firearm? If yes, why. Have you considered getting rid of them. If no, we will refer you to the state confiscation authorities.