like was said earlier... already laws against felons and domestic violence offenders from possessing guns. DV offenders for life with no possibility of restoration under federal law. considering what qualifies as DV, don't get me started on that bullshit.
but, back to the topic at hand... also laws against anyone who has had a mental health commitment order entered against them from possessing a firearm. in ND i think its 3 years from the date of the order or the end of the term of commitment. can't remember. you can petition to get them restored though at least under state law. same with most felonies. so, in short, this proposed law is stupid. if someone is dangerous to themselves or others because of their mental state, use the civil commitment process. if they are threatening others, get charges filed and ask the prosecution and/or the judge to restrict their right to own firearms while on probation if your allegations have enough evidence to convict.