You're right, they can't hold a flood back with their bare hands. But the world's greatest economic power could build a simple and effective pair of fences like the one on the bottom of the picture for a tiny pittance, probably less than the cost of one nuclear submarine, for example.
But Bush won't do his clear duty, under Article 4 Section 4 of the Constitution.
A fact which incresingly tempts me to become a single-issue voter.
I'm not there yet, but I'm not getting any less pissed off either.