Geez, I don't think US is in danger of being invaded anytime soon, that's for sure. That just makes me laugh. The world is much to integrated for such anachronistic conflicts among developed, industrialized nations.

Reminds me of an episode of The Simpsons:

Homer: You couldn't be more wrong, Lisa. If I didn't have this gun, the King of England could just walk in here any time he wants, and start shoving you around. [pushing Lisa] Do you want that? [pushing her harder] Huh? Do you?

Deterant/protection to/from home invaders is a better argument imo.

You lost my vote Bossnine! Oh wait, I'm not American, and I don't vote