Election (1999)

Jim McAllister, a well-liked high school government teacher, can't help but notice that successful student Tracy Flick uses less than ethical tactics to get what she wants. When Tracy runs for school president, Jim feels that she will be a poor influence on the student body and convinces Paul, a dim-witted but popular student athlete, to run against Tracy. When she becomes aware of Jim's secret involvement in the race, a bitter feud is sparked.

Source: TMDb