It's an excellent school but also one of the worst of the Left-leaning /preaching institutions out there. I do not question their expertise in medicine (I have been treated by their doctors and they are the best in class), however, politics and world affairs, forget it.
I remember Fox news broadcasting from the Penn campus during the election year...well, you can imagine.
Yep... lots of lefties. However, there is a large conservative presence on campus. 700+ members of the College Republians, for instance. Keep in mind that there are a lot of Wharton supply-siders and liberal arts security-focused people like myself.