One of the major factors in transforming Ronald Reagan from a New Deal Democrat into a conservative Republican was his confrontation with Herb Sorrell in 1946-47 Hollywood. Head of the Conference of Studio Unions, Sorrell was a veteran union organizer. He was also a secret member of the Communist Party and a frequent contact for Soviet intelligence agents.
Sorrell in 1945 launched a strike to ensure that his union dominated Hollywood labor. Sorrell had no problem using physical intimidation to reach his goals. This was demonstrated at what has been called the Battle of Burbank on October 5, 1945 when 800 members of the Conference of Studio Unions battle with police of the Los Angeles Police Department, using knives, bats, chains and pipes to shut Warner Brothers down. The violence shocked Hollywood and attracted nationwide attention and led to a negotiated settlement of the strike.
In 1946 the Conference of Studio Unions launched a new strike with Ronald Reagan witnessing in person the use of violence to enforce a picket line at Warners Brothers. In tandem with Roy M. Brewer of the International Alliance of Theatrical Stage Employees, the stage hands union, Reagan, as President of the Screen Actors Guild waged an unremitting, and successful, struggle to rid Hollywood of the violent Communist dominated union. Go here for the details. Reagan remained a liberal Democrat, vigorously supporting Harry Truman’s re-election in 1948, but his involvement against the Communist dominated Union set him on a trajectory towards conservatism.