Not withstanding several treaties banning such weapons, the total lack of any foreseeable need, and massive Federal deficits, CNN reports: Air Force seeks Bush nod for space weapons
Near-Earth space is already cluttered with junk that comes down along with meteorites, so now they want to launch more debris into the mix.
I would make this incredibly stupid concept dependent on making the current anti-missile system work as advertised before any research could start, which would eliminate an possibility of this ever occurring.
I have a sneaking feeling that the analysis was along the lines of: "Hey, the Invaders always win! No matter how many you eliminate more keep showing up to eliminate your ground defenses. You can't win against a space-based weapon." Unless, of course, you send a dozen people infected with Ebola across the Rio Grande, or have them fly into major metropolitan airports.
Space Command should concentrate on dealing with Asteroids™