It depends on the position. It's a lot harder to get work as a government employee without a degree in the US, but contractors seem to have more flexibility. I worked for a government agency while I was in the military, and I can't even get an interview for the exact position I was doing for a couple of years because I don't have a degree. I know a few people who've missed out on jobs because the government position has a hard requirement for a degree, even if it's not relevant to the position (like computer science for a security position).