We have WMD's, and we call them nukes. And we may well be about to destroy each other. However, laser defense systems might fix the problem.
Yea, laser-pinpointing nukes while in their flight could stop destroying a country, but radiation in the air would be bad.
I'm pretty sure they have something better than laser-pointer guidance-systems.
I was meaning lasers to shoot nukes down. We almost have the technology to put a laser in a Boeing 747 that can shoot down a nuke from a couple km away.
The fallout could still be bad, nukes work by blasting a few hunks of uranium (or whatever) at each other to gain critical mass. If you sliced the nuke right, you could separate them, and they would stay in two pieces.
My dad worked on bombs. Gyro bombs. These bombs had heads that spun around. and it was laser guided. (It falls out of a plane and the front of it spins around towards the laser and the jet propeller in the back thrusts it at the area it's pointing) He was in the army. Although I've never seen him in the army since I was born. He has alot of stories. He was flown to Germany... He went everywhere. He even accidentally drove a tank underwater (I think it was just an Armored Vehicle) but It still worked underwater... Never knew tanks could do that.
http://en.wikipedia.org/wiki/Tank#Mobility