Edward Murrow was exercising his rights in the sixth clause of the First Amendment, to petition the government, and used his voice to make a change. Thanks to the third clause of The First Amendment which states that Congress are not to abridge the freedom of the press, Murrow was successful even though people did try to get in his way. He was eventually appointed as Director of the U.S Information Agency in 1961 by John F. Kennedy. source
Even though the First Amendment is in place for people like Edward Murrow to be protected, sometimes speech is suppressed because certain people or groups are afraid of being called out. The chilling effect is the concept of preventing free speech and association rights protected by the First Amendment as a result of government laws or actions that appear to target expression. The Chilling Effect was put into action during the McCarthy era. For more information on this you can view this article.
The relationship between the press and the government is a complicated one. The press is often overly critical of the government or does a great job at bringing up issues that need to be address more in depth. Government leaders are often under pressure. Check out this New York Times article that discusses the modern day press and its relationship to the Trump administration.