Pro-Palestinian protesters have taken over a building at Columbia University, marking a significant escalation for nationwide demonstrations that experts say have pressed and sometimes strayed from what is legally permissible. While protesting is a sacred right in the U.S., all the more cherished on college campuses, hundreds of students have been arrested in multiple states as administrators and elected officials try to enforce what they see as essential boundaries. Legal advocates say activists must understand the right to protest in different contexts, such as if they are at a private or public school, whether they are protesting indoors or outdoors...