[9] In 1967, Butler was preparing to run for the US Senate when he began to discuss the Vietnam War with a young student who worked as a gardener at his home.

[4] Hair opened on Broadway in April 1968 and became a huge success, running for 1,750 performances, and leading to many other productions.

[3] He held "Cause" meetings in Oak Brook, Illinois in the summer of 1969 with Tom Smothers, Peter Yarrow, and Black Panther Fred Hampton, among others.

[3] Butler dated Candice Bergen, Nati Abascal and Audrey Hepburn, with whom he had a relationship in the early 1950s before her marriage to Mel Ferrer.

Butler was involved in Hepburn accepting a role in the New York production of the play Ondine, where she worked with Ferrer not long before marrying him.