Intelligence and overall personality in the US Army (or more or less any organisation, again generally American) is determined by rank.
If you're a General or CEO, you'll be a stubborn hardass who refuses to listen to anyone. You tend to say, "Security, get this man/woman/tentacled alien out of here" rather a lot. ORDERS ARE ORDERS UND YOU VILL OBEY!
If you're a mid-level officer, you'll be the only person in your organisation at that rank. (Exception: if there's another person at the same level, or preferably a level above you, he/she will hate your guts and do everything possible to undermine you.) You will also be the only person in your organisation who's right. You'll be the only person working in THAT SPECIFIC DEPARTMENT of your organisation that has anything to do with the problem at hand. And no one will listen to you. Your name is probably Cassandra.
If you're a lower-level officer (Something like a Sergeant), you'll be a bit dumb, totally unable to figure out the problem, but you'll be kind-hearted and pretty good with anything that goes BANG. You'll probably die.
If you're a security guard/bottom level operative, you'll have the intelligence of pond scum. You'll stop the good guy from getting where he needs to but lay out a red carpet for the baddie. You'll die - and you'll deserve to. And your family won't miss you.