It's nearly impossible to defend against so I'm expecting President Obama to scrap the project or at the very least, share it with an Islamic country. I hope I'm wrong.
The weapon known as a railgun doesn't even use explosives. It's powered by electromagnetic rails that accelerate a hardened projectile faster than a speeding bullet. Hopefully, if Obama doesn't screw this up, it will keep us ahead of the Chinese and Russians.
Unlike a recurve bow, where the arrow loses velocity once the string is released, the railgun projectile gains speed as it travels the 32-foot barrel and exits at over a mile per second. That's more powerful than a locomotive. That's Mach 6 fast!
Rather than going "Boom!" the railgun projectile goes "Bahdahbing!" not unlike a baseball bat upside the head.