Around the country, thousands upon thousands of students walked out of their classrooms on March 14 to peacefully protest inaction on gun laws in the aftermath of the deadly Florida school shooting last month. And then there was Antioch High School near Nashville, Tenn. Some of the students who walked out of class at the school Wednesday pulled down an American flag hanging from a flagpole, video shows. Some students jumped on a police car, Nashville police told News Channel 5. And more generally, there appeared to be chaos on school grounds, judging from videos posted on Facebook. Those videos...