Let me be, admittedly, mean, but to make a point I can't figure out how to make any other way. Those who oppose the right to keep and bear arms are not as a rule the kind of people who would, or could, take down a nut waving his gun at the kids in a McDonalds. Those who oppose gun rights are more like the kind of people who when the incident was over would write a sensitive essay about how it felt to come face to face with one's existential powerlessness when faced with the sudden force of a sick man who alas shot two kids right in front of me. You may mean to be helpful in the abstract, but you are not helpful in the particular.
Ms. Noonan is a national treasure!
There's the "tag" line you've been looking for.