From the Spokesman:

People convicted of minor domestic violence offenses can be barred from possessing guns even in states where no proof of physical violence is required to support the domestic violence charge, the Supreme Court ruled Wednesday.

[ . . . ]

The Obama administration had argued that the lower court decisions would effectively nullify the gun ban in dozens of states where misdemeanor domestic violence laws don’t specify the degree of force needed for conviction. That would frustrate the intent of Congress, the administration argued, which was to keep firearms away from anyone found guilty of misdemeanor domestic violence.

Details of the actual case involved in the decision are at the link. I suppose it’s like restraining orders in some places; no real evidence of a threat is required to obtain one.