If I recall from my experience last year, there's a hold list that feeds into either alternate or waitlist. Then there's a waitlist & alternate list. The waitlist is accepted but just waiting for a spot (bc they can't have more than 171 students because of congressional requirements), and alternative has to wait for the waitlist to finish.
I've been told a lot of people get taken off the waitlist and some years they make it all the way through. This is not necessarily the case however as I made the waitlist last year but ultimately wasn't accepted (it also varies branch to branch along with year to year so YMMV). I can confirm though that if you have to reapply, you still have a shot at getting in. So if you're really interested in USU, and things don't work out anywhere this cycle definitely consider reapplying like I did!