Perhaps no image better summarizes the problems with “Good Night and Good Luck,” George Clooney’s new movie about the legendary journalist Edward R. Murrow, than the photo that appeared in the arts section of the New York Times on Sept. 23.

It accompanied a story brimming over with lavish praise, as articles about this movie – and, for that matter, articles about Murrow – usually do.

Clooney and his co-stars, Robert Downey Jr. and David Strathairn (who plays Murrow), are shown in a scene set in 1954 in the news room at CBS, the network where for 25 years Murrow reigned as a huge star and where even today he is revered as an exemplar of TV news.

Clooney’s movie, said the Times story, is “a meticulously detailed reconstruction of an era.” Yet looking at the picture I couldn’t help but notice that nearly every detail was wrong.

The CBS logo on the wall isn’t the logo CBS used in 1954.The actors’ clothes are from a later era, too. So is the telephone on Murrow’s desk. And best of all, sitting next to the phone, is a ribbed plastic bottle of drinking water, circa 2005.

You can just imagine the film crew’s earnest young gofers scanning the Internet, pestering old folks, maybe even consulting books in an effort to pin down what kind of bottled water this Murrow dude drank back in 1954: Was he, like, a Fiji man, or did he go with the more down-market Deer Park?

The worship of Murrow has infected U.S. journalism for a half-century, and now that it’s spread to Hollywood it’s gotten predictably dumber. Yet its essence remains unchanged: The idolaters insist on seeing Murrow as they want to see him, rather than as he was.

The Murrow myth first impressed me several years ago, when I was reading yet another Murrow hagiography called “Murrow’s Boys.” The book’s theme was that after Murrow’s retirement in 1961 TV news entered a sad decline “away from a commitment to news and public affairs and toward lowest-common-denominator programming.”

This sentence carried a strange echo, and I went to the library to trace its source. And sure enough, as you look through the literature of TV news – if “literature” is the word – you discover that the date of the decline of TV news is impossible to pin down. It always seems to have occurred the day before yesterday.

CBS newsman Charles Kuralt dated it to the early 1990s, when “the bean counters” took control. (Kuralt retired in 1994.) Walter Cronkite said the high standards of the “Murrow continuum” ended in the early 1980s. (Cronkite left his anchor’s job in 1981.)

Cronkite’s colleague Eric Sevareid, however, said the decline hit in the mid-1970s. (Sevareid retired in 1977.) Producer Fred Friendly, whom Clooney plays in the new movie, said the great days of TV journalism had ended by 1966. And guess what: Friendly retired from CBS in 1966.

In fact the decline of TV journalism was first heralded almost a decade earlier by Murrow himself, in 1958, not long before his own retirement from CBS. TV news, he declared in a speech, had abandoned itself to “decadence, escapism, and insulation.”

This self-serving romanticism is Murrow’s bequest to the journalism trade. He was a brilliant showman himself, a mythmaker whose most exquisite creation was his own reputation for unimpeachable integrity. Doggerel from the time captured the Murrow image: “No one’s brow furrows, like Edward R. Murrow’s.”

Yet a careful reading of even the Murrow hagiographies reveals a long list of what would be deemed, by the standards of contemporary journalism, serious professional transgressions.

Early in his career he padded his resume, claiming a degree he didn’t have from an institution he didn’t attend. He offered to pay for interviews from newsmakers, and many of his broadcast interviews were scripted. He and his staff routinely received side payments and perquisites from their broadcast sponsors. During the Korean War he deliberately mischaracterized film footage on the air for dramatic effect.

More generally, he shamelessly mixed the values of entertainment and news, foreshadowing the infotainment success of Oprah. He often crossed the line from analysis to advocacy – even secretly coaching a presidential candidate, Adlai Stevenson, in hopes of helping him win the 1956 election.

All of these problems are passed over or ignored when journalists gather to celebrate the career of Murrow, imagining a journalism Eden before it was brought low by the corruptions of commerce and show biz. In place of facts and history is a gauzy moralizing of the kind you’d find in a children’s book, or a Hollywood movie: Murrow the silver knight battling evil network executives, profit-crazed corporate sponsors and hypocritical politicians.

What makes this all the odder is that journalists are the ones who are doing the moralizing. We like to think we’re a hard-headed and skeptical bunch, journalists do. It turns out that we need romantic myths as much as anyone else.

Mr. Ferguson is a columnist for Bloomberg News