An Enemy of the People (1978)

In this adaptation of a Henrik Ibsen play, Dr. Thomas Stockmann (Steve McQueen) is a small-town physician who realizes that the local tourist destination, a hot spring, is dangerously contaminated. Thomas warns his brother Peter (Charles Durning), the town's mayor; Peter, however, is more concerned with cashing in on the spring than ensuring public safety. In order to keep the spring open, Peter and the town council destroy Thomas' reputation as he tries to tell the public of his discovery.