Then you have stop-loss and callbacks...
I served during the end of the cold war. We had no problems making numbers. I joined around the time Gorby took over in the USSR. We had a larger military. What is the problem with our youth? Seriously. Our nation was attacked, and we can't get people to join. We thought that nuclear war could happen. Worldwide conflict, yet we joined. Now, with a smaller military, huge cash bonuses (that would have come in handy for me), we are now looking to oursource to foreign labor.