W. Joseph Campbell is a tenured full professor in the School of Communication at American University in Washington, D.C. He is a former professional journalist, having reported for the Cleveland Plain Dealer, Hartford Courant, and the Associated Press in a 20-year career that took him across North America to Europe, Asia, and West Africa.

The evidence that the mythical “Cronkite Moment” was of minor consequence is compelling and multidimensional.

The “Cronkite Moment” was the televised report in February 1968 when CBS News anchorman Walter Cronkite said the U.S. war effort in Vietnam was “mired in stalemate.” Legend has it that President Lyndon B. Johnson was profoundly moved by Cronkite’s assessment.

Among the elements of the minor-consequence brief are these:

• Cronkite said nothing about the war that hadn’t been said by leading journalists many times before. By early 1968, “stalemate” was a decidedly unoriginal way of characterizing the conflict.
• Public opinion had begun shifting against the war months before Cronkite’s commentary. Indeed, Cronkite followed rather than led the changing views about Vietnam.
• Johnson did not see the Cronkite program when it aired on February 27, 1968, and remained publicly hawkish about the war in the days afterward.
• Cronkite, until late in his life, pooh-poohed the notion his pronouncement had much effect on Johnson, likening its impact to that of a straw....

But little in the minor-consequence brief has kept historian Douglas Brinkley from offering in his new book about Cronkite a glowing, hagiographic interpretation of the “Cronkite Moment.”

Brinkley’s hefty biography is eager to find exceptionality in the “Cronkite Moment,” asserting that it “guaranteed” Cronkite’s “status as a legend.”

Brinkley, however, offers more assertion than compelling evidence in writing that the “aftershock” of Cronkite’s report about Vietnam “was seismic” and in declaring that the report “signaled a major shift in the public’s view of the war.”

As evidence of the purported “seismic” effect, Brinkley claims that Cronkite’s assessment “opened the door for NBC News’ Frank McGee to take a similar stand in a documentary on Vietnam that aired two weeks later.”

But as I point out in my 2010 book, Getting It Wrong, Cronkite’s “stalemate” characterization was “far less emphatic” McGee’s on-air remarks on March 10, 1968. “The war,” McGee declared on that occasion, “is being lost by the administration’s definition.”...