No matter which candidate wins this election, he is going to have some serious bills to pay after covering the cost of the war in Iraq, the economic bailout, and the rapidly approaching fatigue life of many platforms.
One of the prime directives for any politician is to protect and grow jobs...in each and every district. Defense contractors, be they considered patriots or death merchants depending upon your political leanings, employ a lot of folks. Neither party really has the political backbone to slash jobs that way, I believe.
The real cost driver for the DoD is personnel costs, both in "now" dollars and banking for the retirements. Cutting people from the military is never an easy thing to do, but it is a valid option...after all...who advocates/lobbies for the first 3,500 sailors "right-sized"...or the next batch of 5,000 etc...
Realistically, I would expect a some of both...cut backs in weapons systems procurement and manpower reductions.
With regards to the military retirement...ohh boy...that's a big minefield. No one who has earned the 20 year good deal wants to lose it...but who wants to wait until that point to receive any benefits?
The thing to keep in mind is the simple fact that this is an all volunteer force...whatever gets cooked up by the politicos needs to be pretty attractive...and also needs to be flexible enough to avoid the already mentioned negatives of folks hanging on for dear life until the big TWO ZERO.