Depending on the program, you're going to have to take math. I'd rate somewhere in the 3-5 range. But the math shouldn't be incredibly difficult, stuff like basic calculus, linear algebra, set theory, that sort of thing. As for using it in the real world, trust me, anything you do in the real world for a job is going to be simple compared to the math you have to learn for the degree.
So here's a question for you, and some food for thought. Since you're interested in both poli sci and computer science, would you be happier using your CS knowledge to do something Poli Sci related, or would you rather do a pure CS job? (I can't imagine a computer science job with a poli sci bent but who knows). After college it may be easier initially to get a job with a pure CS degree, but having good CS knowledge and a Poli Sci degree could put you way ahead of your peers since you'll know how to program simulations and whatnot. Personally, I'd go for the Poli Sci degree with a CS concentration. Without knowing you, I'd bet that you'll be happier in the long run, and it will likely be a lot more interesting. Plus if the poli sci thing doesn't pan out, it's easy to find CS classes to get a full degree.