Traditionally, clashes over academic freedom have pitted politicians or administrators against instructors who wanted to express their opinions and teach as they saw fit. But increasingly, it is students who are invoking academic freedom, claiming biased professors are violating their right to a classroom free from indoctrination. For example, at the University of North Carolina, three incoming freshmen sued over a reading assignment they said offended their Christian beliefs. In Colorado and Indiana, a national conservative group publicized student allegations of left-wing bias by professors. Faculty received hate mail and were pictured in mock "wanted" posters; at least one college...