The protagonist (Willie Stark) first teaches himself law and becomes a lawyer, championing the local people and gaining popularity. He then decides to go into politics. Willie seems to work for the people. So the people support him from the bottom of their heart. Along the way, however, he becomes as corrupt as the politicians he once fought against, and Willie starts acting like a dictator. This is usually the way an innocent man turns into a politician in the States---if not in the world political scenes. Adam Stanton (surgeon) assassinates Willie after he has successfully got away with an impeachment investigation because he tries to discredit the reputation of his uncle (ex-Attorney General) who commits suicide and because he had an affair with Adam's sister. This movie was loosely based on the real-life Louisiana Governor, Huey Long, who was assassinated on September 8, 1935. Long was was at the State Capitol attempting to oust a long-time opponent, Judge Benjamin Henry Pavy. If it passed, Judge Pavy would be removed from the bench. Judge Pavy's son-in-law, Dr. Carl Weiss, had been at the State Capitol waiting to speak to Long. The doctor tried to see Long three times before but was brushed off each time in the hallway by Long. Dr. Weiss approached Long for the third time and fired a handgun at Long from four feet away, striking him in the abdomen. Long's bodyguards returned fire, hitting Weiss 62 times, and killed him at the spot. Long was rushed to the hospital but died two days later.

The movie does a good job of capturing the essence of the book even though the screenplay simplifies its more complex plot line for reasons of pace and narrative. However, one would get more from the movie having read the book.