As I see it, defensive space weapons are unecessary and much too costly. Right now we're just starting to perfect lazer weapons that can destroy a tank or a missile from miles above. All they need to do is set up a grid of defensive lazer-turrets in key strategic areas on the North American continent, similar to the DEW line.
As long as our enemies don't get some Imperial Star Destroyers, we'll be just fine.:thumbsup: