The 1980 Defense Officer Personnel Management Act mandates that officers passed over twice for promotion are required to be discharged from the military. So ye

The 1980 Defense Officer Personnel Management Act mandates that officers passed over twice for promotion are required to be discharged from the military. So yes, if you are not promoted, you don't get to stay - you are actually fired. They have modified this for some positions like flight instructors who they want to keep. But in general it's up or out in military - that means fired before you get your pension.