I had a thought that apparently Clueless Joe didn't consider.
Assuming females are drafted in equal number with males, the following problems will arise:
-Females tend to get injured more in basic training. This will be especially true in the Marine Corps, where women have to go through the same training as men.
-There will probably be more sexual harassment/misconduct issues arising from this. I'm not sure how you would remove the temptation...have an all-female unit? Sounds like reverse discrimination to me.
-There should also be a lot of lesbians joining up. Obviously, the military doesn't want gays because their leadership has been brainwashed into right-wing nonsense.
-Forcing women to serve in the military also raises issues of fairness. I'm sure there are a lot of women out there who wouldn't be prepared/willing to serve and wouldn't be physically fit, so the chance of a washout increases.
-Over time, more women in the military means more female leadership. I'm not sure if the military would feel comfortable having female generals and such running around.
Forcible service in the military in 2009 would be a public relations nightmare...