Take the approach of "all right thinking Americans can have a licence and own a weapon, it's only the criminals and lunatics and foreigners that can't".
In many ways this is the case, but...
The definition of 'criminal' is ... a bit arbitrary in some ways. If you buy a DVD and rip it to get a version you can play on your tablet while camping, you have committed a felony, and if caught and convicted, you will lose, in many states, your right to vote, to own a gun, to live in certain areas of town, and so on. Similarly if you get caught with any amount of recreational drugs, depending on who catches you and where.
Given that many criminals are armed, that leaves you a prime target for home invasion, hot burglary, mugging, etc. If you get a gun anyway and get caught... that's also bad to very bad. It seems to me that multiple felony convictions can set you up for a lifetime in prison, but I don't know the details.
I believe that various rights organizations (not gun organizations) are now looking at this as a possible form of discrimination, particularly when a lot of arrests are racially disproportionate, and some of those populations are at greater risk of violence and so might need a gun more.
It's a complicated issue, and simplistic solutions do not work - just look at Chicago.