The Supreme Court quietly handed gun control advocates a small victory

[Igel]

4. Probably not.

The underlying law, making misdemeanor domestic violence grounds for barring gun possession, was the result of a SCOTUS case (as yesterday's SCOTUS decision indicated). Domestic violence was affirmed even then, to little outcry.

There was no challenge by anybody to the domestic violence provision itself.

This was a clarification of the language. The huge outcry is primarily attributed, not real. It's still a question, as far as I know, as to how many states this would apply to--just those with a distinction between reckless vs intentional domestic violence, so that accidental injury in the home can be construed as "domestic violence" and not something else. Somebody's almost certainly done the due diligence to determine how many states that applies to, but the numbers are likely to be squishy.