Space is already militarized anyway. Spy satellites, telecom sats being used to gather intel, and god only knows what else. I wouldnt be surprised if we had a 'Rods from God' setup somewhere out there just chillin.
There is also counter 'space military'. You'v got the Chinese demonstrating that they can blow up satellites, and the US doing the same thing.
The idea itself is stupid when satellites are already used and depended on heavily by the US military.
Here ya go, this is a good read. Not really the best description of the Rods from God system, but a good read none the less about this subject.
http://www.sfgate.com/cgi-bin/...1.DTL