IT was 30 years ago. One of the greatest dramas Washington has ever seen began April 22, 1954. The ''Army-McCarthy hearings'' ran for 35 days and attracted as many as 20 million viewers at a time. When the hearings were finished, so was Sen. Joseph R. McCarthy (R) of Wisconsin, although he didn't know it. He was, asserted Richard H. Rovere, correspondent of The New Yorker, ''the most gifted and successful demagogue this country has ever known.''
Maybe yes, maybe no. But for a journalist, McCarthy created a tension that makes my heart throb even now, as I walk by the National Press Building and think of dashing off to the jampacked Senate Caucus Room. Thirty years ago! We wondered what the United States would be like in April of 1984.
People who didn't live through McCarthyism cannot really understand it. McCarthyism was a mass yielding to the fear that somehow a great nation had been betrayed into the hands of conspirators. Or, if not betrayed, that we might have been lax in protecting ourselves against such a betrayal. It was a mood made for political exploitation, and McCarthy was there to use it. Roscoe Drummond wrote in this paper May 12, 1982, ''He had run out of effective issues in his campaign for the Senate. He ended up in Wheeling, W.Va., on a five-state fund-raising campaign and delivered a speech written by a newspaper friend of his. It was a speech proclaiming that the federal government was infested by card-carrying Communists and fellow travelers. He found that he had hit pay dirt and kept it up from then on.''
It was surprising that McCarthy got the support he did. Of course Democrats called it a red herring. This led to heated replies: The Democrats were ''soft'' on communism. Sen. Robert A. Taft, a careful but partisan man, quickly responded. He charged that ''the greatest Kremlin asset in our history has been the pro-Communist group in the State Department.''
McCarthy's power was such that Gen. Dwight D. Eisenhower yielded to it in his 1952 presidential campaign. McCarthy recklessly attacked Gen. George Marshall for not having pressed the fight against the Communists. General Eisenhower was to defend his old friend in a speech at Milwaukee. But when the press got the final text of the speech, we found that the earlier defense of General Marshall had been taken out.
In 1954 the country seemed safe enough from Communists with Ike in the White House. Senator McCarthy, however, continued his attacks and argued that the Army was lax. This led to a showdown with high officials and, by extension, with the White House. McCarthy was then accused of using improper means to obtain preferential treatment for Pvt. G. David Schine, a former consultant of his subcommittee. McCarthy charged that the Army tried to pressure him to call off the investigation.
The climactic clash came when the senator accused a young member of Joseph N. Welch's law firm - the special Army counsel - of Communist associations. In an unforgettable moment Welch replied, ''Until this moment I think I never really gauged your cruelty and recklessness.'' And he asked, ''Have you left no sense of decency?'' As the session ended, spectators applauded, but the senator had no sense that he had been destroyed.
That was the drama as we hurried from the Monitor bureau to the daily sessions in the Caucus Room: The antagonists sat behind a 26-foot-long mahogany table in the ornate marble room, three stories high. At that time it was the largest crowd ever to view a congressional hearing. Chairman Karl E. Mundt (R) of South Dakota pleaded for decorum. But 17 minutes after the start came Senator McCarthy's first ''point of order, Mr. Chairman'' - a procedural subterfuge to interject commentary. Yes, he charged, the Army brass was trying to block an investigation of domestic communism.
The charges were too preposterous. Joseph Welch was too effective. The media turned against the petulant Senator McCarthy. A book by Thomas C. Reeves noted: ''A series of well-documented articles in The Christian Science Monitor concluded that in fourteen months of public hearings the McCarthy subcommittee had failed (1) to find a single Communist spy whose guilt stood proved in court, (2) to secure a single indictment against anyone it charged with treason, (3) to uncover a single proved Communist working on a secret defense job.''
On the evening of Dec. 2, 1954, the Senate spoke. It voted 67 to 22 to ''condemn'' Mr. McCarthy. Great was his fall, and there was no way of putting him together again. He never recovered.