For the latest evidence of the town-gown divide, look no further than New Jersey, where earlier this summer residents of Princeton banded together to sue the prestigious school in their backyard. The residents argued that Princeton University, which boasts the largest endowment per student in the country, should no longer be entitled to its tax-exempt status because the school makes money—from its scientific patents, ticketed concerts, on-campus eateries and more. The Ivy League school is operating like a business, the plaintiffs say, so the tax code should treat it like one.

The...