Dangerously Close (1986)

Rebel without a cause or a clue at an elite but uptight High School discovers some of his classmates have formed an even more elite clique more or less hell-bent on ridding the school, and quite possibly American society, of what they deem to be its undesirables because of ethnicity, politics, etc. Our hero recruits a teacher and some other "less desirable" classmates to undermine the elitists, and, naturally, things get quite violent.