Most Government agencies won't look at you without a Bachelors, even with military service. (I actually think the FBI/CIA requires it)
Now if you get a Criminal Justice/Criminology bachelors then go back with your military background, you'll get a huge boost over other candidates. CJ is a pretty easy major, I did it for 3 years and had no problems with it.
You could also look into Law Enforcement, but you're still going to want at least an Associates to get looked at by bigger departments.
Look at this way, the military is going to pay for you to go to school. Go do it. My brother is on the GI Bill and its worked damn good for him. Pay for school, his books, and his rent. And he still has plenty of left over money for other things.