“Nothing in our opinion should be taken to cast doubt on longstanding prohibitions on the possession of firearms by felons and the mentally ill,” Justice Scalia added. Government buildings in general could still ban guns. And the court said it had no quarrel with “laws imposing conditions and qualifications on the commercial sale of arms.”It hardly needs to be explained to anyone of average intelligence that there is nothing in the United States Constitution which forbids legislation prohibiting people licensed to own and use a firearm from selling, giving or bequeathing that firearm to a person who is not licensed to do so (the examples given being felons and the mentally ill).
Your first clue that McArdle doesn't know what she is talking about is that she can't bother to get simple facts straight from news articles written at a fourth grade level, even though that is part of her job. McArdle is no more capable of understanding a Supreme Court opinion than she is of writing a blog post which doesn't demonstrate what a dolt she is, at great length.
Update (12/19): Link fixed.