The Larger Issue
I'm a political scientist, with at least a little political intuition. If you want to stem the tide on this, IMHO, you need to tie it to a larger philosophical and emotional theme. And the one I'm thinking of is the one demonstrated by that fourth hijacked plane on 9/11. Citizens are the "last line of defense," against the threat of totalitarian terrorism, so diarming them is a profound "mistake in doctrine." Tied to this is the idea of a different relationship to the state, that involves more responsibility adopted by ordinary Americans for crime and for quelling terrorism. This is a simple, comprehensive, theme that not only fits a lot of situations impacting on gun laws, but also one of the main themes in American politics (individualism and anti-statism). More to the point It's precisely why I changed MY mind on these issues. It's an easy and intuitive story to tell, and it'll put the opposition on the run.