There was an old saying "Poli Sci, CPR High !" There used to be a number of engineering professors that the took a perverse pleasure in kicking Midshipmen butt academically.
Seriously, it's an individual choice --what do you enjoy doing ? I went in thinking I wanted to be Aero Engineer, but always enjoyed (and was better at) reading and writing than math. My decision was made when we did our majors orientation.... a Marine Capt., Poli Sci prof with wings gets to the front of the room, and asks how many people are thinking about Aero because they want to fly, a handful of us raise our hands, and he looks at us as says "that's BS, you don't need to be an Aero major to fly, you push the stick forward ..houses get bigger, pull back..they get smaller. I was a Poli Sci major and I'm the best damn pilot in the Marine Corps....." I was sold !
Political Science at USNA is not like a poli sci major at Georgetown or State U. You still get a technical curriculum with all the courses necessary to perform in the fleet. Learning to read and write was the bonus, and helped me in both my Naval and law careers.
