Why is our military budget so bloated? I very much recommend this post
Basically, the answer is the expansion of petty bureaucratic fiefdoms . The army is famously at odds with the navy, air-force etc. So, when we make the army bigger (if the president got us into a quagmire), then the air-force gets a similar budget increase. Need I point out this is a bogus-bullshit way to appropriate resources?
There are other reasons as well. There are of course their is the contractors who give money to the president and to congress, and the congress men who will fight tooth and nail to keep military bases in their districts from closing down. The Bush years have been a heyday for big defense contractors (surprise).
Military spending is the least efficient type of spending. In the Reagan era, we famously paid $500 for a toilet seat. It's still that bad. Time to bring it in line.
(Posted by Ewan)