Happy to chime in here- Wes grad myself who did not major in CSS but did double in two social sciences, one of which was GOV (the other ECON).
CSS borrows faculty from other social science departments- it does not have its own faculty. Thus, CSS is technically it’s own entity under the social science aegis. It takes faculty from ECON, GOV, PHIL, and SOC. That said, the professors involved in the program see it as their baby and are often much more involved in it then they are with their “true” departments.
The econ in CSS is more heavy in political theory/philosophy that in the core ECON major- you will not use a ton of calc and will not really get into as much econometrics, for example. Sure, you’ll see some economic models but you’ll actually read the General Theory front to back instead of digging through primary research about, say, interest rates. Vastly different ballgame.
CSS only takes about 30 students per year and they must apply for entrance in the major at the end of their freshman year, instead of declaring during their sophomore year as is the case for the rest of the social sciences. Your soph year in CSS in particular is a bootcamp, broken into distinct chunks of say, heavy philosophy reading of several hundred pages a week followed by the student writing up a 5 page paper- every week. The paper is not graded, instead your only grades are noted at the end of the year in which you go through a grueling week or so where you are given a 24-48 hr period in which to respond to a written topic, you have a 24 hr period off, then back at it. Your transcript comes with a special note indicating how/why this is done- it comes from the Politics, Policy, and Economy (PPE) curriculum of Oxford, which is notable for producing a large list of British PMs and other heads of state, amongst other notable alums.
I hope you can tell by now how enamored I am of the CSS program at Wes. I wish I had done it- those in my class who did so are to this day very happy with their experiences and among the most successful alums.