The Front (1976)

In the early 1950s Howard Prince, who works in a restaurant, helps out a black-listed writer friend by selling a TV station a script under his own name. The money is useful in paying off gambling debts, so he takes on three more such clients. Howard is politically pretty innocent, but involvement with Florence - who quits TV in disgust over things - and friendship with the show's ex-star - now himself blacklisted - make him start to think about what is really going on.