Fall from grace

I've got an idea for a movie:

A man in his mid 30's gets a law degree and starts his own law firm in 1960's Kansas fighting Jim Crow laws. He becomes a popular civil rights attorney and is frequently harassed and threatened by segregationists and white supremacists.

In the 1970's he starts to lose his way. He freaks out on a woman in the court system who failed to provide him with some documents and attempts to sue her, making her sit on the stand for a week so he can badger her and bring out any embarrassing details of her personal life. He ends up getting disbarred for it.

He starts getting into politics and runs for governor and the senate as a Democrat but can never pull it off. He starts to focus on opposing gay-rights and becomes head of his own church with a focus on how gays are ruining the world and inviting the wrath of God.

He ends up completely deranged and his church becomes a doomsday cult. They start seeing every tragedy as proof of God's anger for tolerance of gays and the church begins harassing victims of popular tragedies and even holding rallies outside the funerals of American soldiers. This leads to a freedom of speech case that goes before the supreme court which he wins, completing a full circle for his role in establishing the parameters of civil rights.

My working title: Fall from Grace: The story of Fred Phelps.