By RONALD KESSLER

Fifty-four years ago today, Sen. Joseph McCarthy started his televised hearings on alleged Soviet spies and communists in the Army. The spectacle grabbed the country's attention for the next two months.

By the end of the McCarthy hearings, the senator's career was over; before an audience that often numbered 20 million Americans, he came across as bullying and unscrupulous. Yet today, more and more conservative writers are trying to vindicate the late senator. Authors M. Stanton Evans and Ann Coulter, for example, have claimed that McCarthy was more right than wrong because he, along with dozens of other anticommunists, was correct that the government was riddled with spies.

The FBI agents who actually chased Soviet spies have a very different perspective.

Robert J. Lamphere, who participated in all the FBI's major spy cases during the McCarthy period, was one. Lamphere also was the FBI liaison to the U.S. Army's Signal Intelligence Service's Venona program, which was intercepting secret Soviet communications. He used leads from the intercepts to work cases involving notorious espionage figures such as Klaus Fuchs, Harry Gold, David Greenglass, Ethel and Julius Rosenberg and Kim Philby.

Lamphere (who died in 2002), told me in an interview that agents who worked counterintelligence were appalled that FBI director J. Edgar Hoover initially supported McCarthy. True enough, the Venona intercepts revealed that hundreds more Soviet spies had operated in the government than was believed at the time.

"The problem was that McCarthy lied about his information and figures," Lamphere said. "He made charges against people that weren't true. McCarthyism harmed the counterintelligence effort against the Soviet threat because of the revulsion it caused."

McCarthy's crusade began on Feb. 9, 1950, when the Republican senator from Wisconsin gave a speech to the local Republican women's club in Wheeling, West Virginia. "While I cannot take the time to name all the men in the State Department who have been named as members of the Communist Party and members of a spy ring, I have here in my hand a list of 205 – a list of names that were known to the secretary of State and who, nevertheless, are still working and shaping policy of the State Department," he said.

However, the next day in Salt Lake City he told his audience that the number of communists was 57.

After the first speech, Willard Edwards, the author of articles in the Chicago Tribune on the communist threat, urgently asked Walter Trohan, the paper's Washington bureau chief, to come speak with him in Edwards's office.

Edwards, according to Trohan, confided that just before the Wheeling speech McCarthy had asked him about the number of communists in the State Department. Edwards gave McCarthy the figure of 205. Now he realized his mistake. "Edwards said it was more or less a rumor," Trohan told me. "It was just a piece of gossip." Bogus figures or not, McCarthy soon became a national figure.

Back in Washington, he told FBI director Hoover that he had "made up the numbers as he talked." Hoover advised him not to give specific numbers in the future.

McCarthy asked if the FBI would give him information to back up his charges. "Review the files and get anything you can for him" was Hoover's order. Result? "We didn't have enough evidence to show there was a single Communist in the State Department, let alone 57 cases," said William Sullivan, who became the number three man in the bureau.

The Army-McCarthy hearings followed a pattern, notes Donald A. Ritchie, associate historian of the Senate. Typically, McCarthy held hearings in executive session first, "like a dress rehearsal," says Mr. Ritchie, who studied the transcripts of the hearings. Mostly McCarthy didn't have any hard evidence against the people he was interrogating; he just hoped to get them to contradict themselves or to take the Fifth Amendment, or to confess.

"He interviewed about 500 people in closed session," Mr. Ritchie told me. "He called about 300 people to public session."

"After they'd testified in closed session, he'd go out in the hall, and he'd tell the waiting press what had just happened," Mr. Ritchie says. "We looked at both the New York Times's and the Chicago Tribune's accounts and then we compared that to what actually went on inside the hearings. What he told the press grossly exaggerated what took place."

As his arrogance grew, McCarthy began accusing President Dwight D. Eisenhower of being soft on communists. Hoover realized the dance was over; just before the Army-McCarthy hearings started he ordered the bureau to cease helping the senator.

During the hearings, McCarthy failed to substantiate his claims that communists had penetrated the Army. He did, however, insinuate that Fred Fischer, a young lawyer at Hale and Dorr, the law firm representing the Army, was a communist sympathizer because he'd been a member of the National Lawyers Guild at Harvard Law School. Supreme Court Justice Arthur J. Goldberg had also been a member of the group, which was alleged to be a communist front.

Upon hearing this accusation, Joseph Welch of Hale and Dorr, responded, "Until this moment, senator, I think I never really gauged your cruelty or recklessness." When McCarthy continued to hound Fischer, Welch said, "Have you no sense of decency, sir, at long last? Have you left no sense of decency?"

A Senate committee concluded that McCarthy's behavior as a committee chairman was "inexcusable," "vulgar and insulting." On Dec. 2, 1954, the Senate voted 67-22 to censure him; on May 2, 1957, McCarthy, age 48, died of acute hepatitis, widely believed to be a result of his alcoholism.

As a top Justice Department attorney, John L. Martin prosecuted scores of spies during a long career, and read many of the FBI's most secret raw files on historic espionage cases, including the files on Julius and Ethel Rosenberg, Judith Coplon, Alger Hiss and Rudolph Abel. "While Venona later confirmed and expanded upon what the FBI knew about Soviet operations in the U.S.," Mr. Martin says, McCarthy used "the umbrella of national security to justify his outrageous practice of besmirching reputations of loyal Americans."

Efforts to vindicate McCarthy overlook the fact that he did not help the cause of dealing with the spy threat. Rather, he gave spy hunting a bad name. In sanctioning McCarthy's intimidating tactics and dishonest charges, revisionists dangerously invite history to be repeated.

Mr. Kessler, a former Wall Street Journal and Washington Post reporter, is chief Washington correspondent of Newsmax.com and the author of "The Terrorist Watch: Inside the Desperate Race to Stop the Next Attack" (Crown Forum, 2007).