What is the author's purpose for the movie "Good Night and Good Luck"?

One of the film's main themes is dissent. Edward Murrow is using his platform as a newsman on national television to oppose the actions of Senator Joseph McCarthy who makes false accusations of Communist influence in order to give himself power. Murrow opposes the Senator's often corrupt and unconstitutional methods. As a result, he uses his influence as a newsman to sway the American public's opinion by airing stories that expose McCarthy's corruption. In so doing, Murrow is putting his job in jeopardy, as McCarthy has a lot of power. However, Murrow believes strongly in his mission and his ability to influence people's opinions in the direction of justice. McCarthy is stripping away American independence and Murrow knows it, so he uses his news program to publicly challenge McCarthy and ask the American people to think for themselves and see the truth in what the junior Senator is doing, rather than allow fear to dictate how the story is received.