Funny timing for this thread. This is on Fox news today:

After trying to hide in a closet, a bat-wielding 14-year-old has no choice but to fight off an intruder rummaging through his Arizona home Tuesday, AZCentral.com reports.

http://www.foxnews.com/story/0,2933,323423,00.html

So I would say yes, a viable defense.