The federal law regulating gun possession, 18 U.S.C. section 922, makes it a crime for many different types to have a firearm in their possession. Those people include:
Anyone who has been convicted of a crime punishable by more than one year
Anyone who is an "unlawful user" of a controlled substance
Anyone who has ever "committed to a mental institution"
Anyone who has ever been dishonorably discharged from the military
In our (limited) experience, many of these prohibitions are rarely prosecuted. But still - federal law states that you permanently lose your right to possess (let alone own) a firearm if you smoke pot on the weekend, or if you were hospitalized for depression once in 1983, or if you were convicted of writing a bad check for $500 (a felony in our former home state of New Hampshire!).
Heller states that the second amendment protects an individual right to own firearms. If so, how can these broad prohibitions possibly be allowed under the constitution?
We'll leave you with that question as we head off for a three-day weekend.