Until 1968, Walter Cronkite believed what his government told him about the Vietnam War. He was an old-school journalist, a patriot, a man who came of age covering World War II as a wire-service reporter and then taking over as the anchor of “The CBS Evening News” at the height of the Cold War. Like most journalists of his generation, he embraced the fight against communism and understood why the United States had intervened in the war raging in Vietnam.

When he’d visited Vietnam on a reporting trip early in the war, he’d been annoyed by the attitude of the young reporters who seemed to be “engaged in a contest among themselves to determine who was the most cynical,” as he wrote in his autobiography.

Cronkite’s nightly newscasts helped shape public opinion about Vietnam, which became known as “the living-room war,” in the words of Michael Arlen of The New Yorker. Until 1968, network news operations tended to edit out the blood and gore and avoid direct criticism of military operations while American lives were on the line. There was no government censorship, but negative news reports infuriated President Lyndon Baines Johnson and he didn’t hesitate to let the networks know it.