In response to the post on the airborne laser system we featured last Monday, Kyle sent along a link to a video that explains another aspect of anti-missile defense.
The missile shield is a layered defense. The airborne laser system is designed to attack ICBMs in the boost phase of their trajectory, i.e. shortly after they've launched and before they've deployed whatever defense systems or multiple warheads they might be carrying.
The THAAD system that's explained at the link is a kinetic energy defense designed to operate against missiles in their final approach to their target.
Give it a look. RLC