Douglas Brinkley’s new biography of Walter Cronkite has sparked an intriguing controversy about the CBS anchorman’s famous trip to Vietnam in February 1968. That’s when, as legend has it, Cronkite was so shocked at the devastation of the communists’ Tet offensive that he went over to see for himself what was really going on. And he concluded the war was a stalemate, probably unwinnable.

Brinkley buys the argument, put forth by the late David Halberstam in his characteristically portentous manner, that Cronkite’s February 27 broadcast, "Report from Vietnam," played a major role in turning Americans against the war and inducing President Lyndon Johnson to abandon his reelection campaign.

Cronkite’s report, writes Brinkley, was "immediately seen as a catalyst by pundits in the Monday newspapers. . . . Cronkite turned dove, and the hawk Johnson lost his talons." This tracks with what Halberstam wrote in his 1979 book, The Powers That Be: "It was the first time in American history that a war has been declared over by an anchorman." Lyndon Johnson was said to have watched the broadcast and exclaimed to his press secretary, George Christian, "If I have lost Walter Cronkite, I’ve lost Middle America."

Harvard’s Louis Menand, writing in The New Yorker, has an interesting take on this. "The trouble with this inspiring little story," he says, "is that most of it is either invented or disputed." He cites W. Joseph Campbell’s 2010 book, Getting It Wrong: Ten of the Greatest Misrepresented Stories in American Journalism, as noting that Johnson did not see the Cronkite report when it was broadcast. Menand recalls a 1979 quote from Christian saying he really didn’t recall what Johnson said in response to whatever or if he said anything at all like what was then being quoted. And Menand questions whether Cronkite’s broadcast had anything approaching the impact now attributed to it.

This is all great fun and the kind of thing the intelligentsia loves to kick around. But it misses a fundamental point that goes to the heart of America’s Vietnam tragedy. If Cronkite did in fact have a major impact on the American consciousness back in the winter of 1968 (and he very well may have), that impact was based on a fanciful interpretation of events.

Stashed away in Menand’s New Yorker piece is a parenthesis that contains this off-hand sentence: "In the end, Tet was a military disaster for the North, but it was a political victory for them in the West." It is now conventional wisdom among American intellectuals of both Left and Right that the Vietnamese communist forces suffered a tremendous blow in that military effort, but the spectacle of such an all-out effort obliterated domestic support for the war in the United States.

Think about this for a minute: Why would a great U.S. military victory in a war undermine domestic support for that war? To probe this question, we must review briefly the details of the Tet offensive.

In the late-January calm of a Lunar New Year cease-fire, seventy thousand communist troops shattered the celebration, attacking more than a hundred South Vietnamese cities and towns. They struck along the coast, then presumed secure. They shelled the big U.S. complex at Cam Ranh Bay and stormed numerous towns in the central highlands. They attacked the mountain resort of Dalat and invaded thirteen of sixteen provincial capitals in the Mekong Delta. They captured the ancient northern capital of Hue and carried the war into the heart of Saigon—even into the U.S. embassy compound.

This was the most daring operation of the war, and Americans watched in horror as the bloody spectacle unfolded on their television screens. They had been told the military situation was in hand, and now those assurances lay shattered in the American consciousness.

But Tet had been a desperation move by North Vietnam, beset by a relentless American killing machine. And the Allied response was awesome. The communists lost ten thousand men in the first few days of the offensive, compared to 249 Americans dead and five hundred South Vietnamese. Overall, throughout the months-long battle, the communists lost nearly forty-eight thousand men. The North Vietnamese had sought to deliver the decisive military blow that would knock the Americans out of the region. They failed.

They failed so miserably that they lost their ability to wage war in the South. Even a year later, as Richard Nixon assumed the presidency, CIA director Richard Helms told Newsweek columnist Stewart Alsop that the communist main force in Vietnam had been decimated in the 1968 fighting so thoroughly that it would take considerable time for Hanoi to rebuild its forces.

Into this military drama, in the first weeks of Tet, comes Walter Cronkite of CBS News. He travels around, talks to people like a real reporter, presumably takes notes. And then he goes home and delivers a report to the American people that totally misses the story. At this pregnant moment of the war, when prospects of victory never looked brighter, he concludes that the war is a stalemate and probably unwinnable.

It isn’t surprising that he would be lauded by David Halberstam as "the most significant journalist of the second half of the twentieth century." Halberstam made a career of attacking what he perceived as the follies of that military adventure. Follies there were in abundance, but Halberstam’s ideological perspective shielded from his consciousness some of the nuanced realities of that agonizing story.

The hawkish columnist Joseph Alsop also brought an ideological perspective to his work, far different from Halberstam’s, and perhaps that helped him see Tet with more clarity. Within twelve days of the start of the offensive, he filed four columns exploring its military ramifications. He pleaded with readers to consider not just America’s painful problems in the war but also the problems of the communist side, which were even more painful. He reported new information suggesting that Tet had cost the communist forces nearly thirty thousand men killed or captured (later confirmed by historical accounts). America, he wrote, stood at a "breathless moment" that called for "stoutness and resolution."

But nobody was listening in the wake of those ominous flickering images in America’s living rooms and the false reporting of men such as Walter Cronkite. America had decided it must extricate itself from Vietnam by extricating itself from Lyndon Johnson.

Much has been written about the military defeat suffered by North Vietnam in Tet and the huge psychological victory it scored at the same time. And inevitably the question has emerged as to whether the American media paved the way for the communists’ psychological victory. Don Oberdorfer, in his book TET! The turning Pont in the Vietnam War, called the battle a "historical anomaly: a battlefield defeat that ultimately yielded victory." But he doesn’t blame the American media. "Unquestionably," he wrote, "there was misreporting of Tet, especially in the confusing and uncertain days following the attacks." But he denied that press reports contributed significantly to the loss of domestic support.

The late Peter Braestrup, Oberdorfer’s Washington Post colleague from those Vietnam days, disagrees in his 1977 book, Big Story. "Rarely," he wrote, "has contemporary crisis-journalism turned out, in retrospect, to have veered so widely from reality." To have such a defeat for the enemy portrayed also as a major defeat for America, he added, "cannot be counted as a triumph for American journalism." It simply isn’t logically consistent.

There’s plenty of room for debate between the viewpoints of Braestrup and Oberdorfer on whether the press contributed to America’s psychological defeat. But there’s no room for debate on what actually happened and how it was covered. And when it comes to Walter Cronkite, it’s amusing to follow the discussion about whether he really had the impact often attributed to him, whether LBJ really equated losing Cronkite with losing Middle America, whether the president’s decision to quit his campaign actually flowed from the anchorman’s "Report from Vietnam."

It all misses the point, which is that on the biggest story of his career, with the world watching and the stakes high, Walter Cronkite of CBS News got it wrong. For a journalist, it can hardly get more devastating than that.

Robert W. Merry is editor of The National Interest and the author of books on American history and foreign policy. His most recent book is Where They Stand: The American Presidents in the Eyes of Voters and Historians (Simon & Schuster).