You won’t be expected to know specific military leaders (other than perhaps the Commander in Chief), but you should be up on current events. In various interviews — for SAs, MOC noms and ROTC scholarships — DD was asked about what the biggest national-security threat to the U.S. is. And in explaining why she might be a good fit for a particular service, she was able to talk about its unique mission and weave in a couple recent events as examples. So you don’t need to know detailed ins-and-outs, but you should be somewhat conversations about macro issues involving the military.