Is it better to pursue an uncommon major?

My son wants to do international relations in college. He is very interested and there are some nearby colleges which offer the major .But he concerned, as they are state universities and not necessarily high tier colleges. He is wondering whether it is a good idea to pursue an unorthodox major, like philosophy, and try to apply a harder institution. his logic says that an uncommon major would have less applicants and thus easier admissions.