This is from Wikipedia, my go-to source for concise summaries:
The Army-McCarthy hearings were a series of hearings held by the United States Senate’s Subcommittee on Investigations between April 1954 and June 1954. The hearings were held for the purpose of investigating conflicting accusations between the United States Army and Senator Joseph McCarthy.
The Army accused chief committee counsel Roy Cohn of pressuring the Army to give preferential treatment to G. David Schine, a former McCarthy aide and a friend of Cohn’s.
McCarthy counter-charged that this accusation was made in bad faith and in retaliation for his recent aggressive investigations of suspected Communists and security risks in the Army.
The media coverage, particularly television, greatly contributed to McCarthy’s decline in popularity and his eventual censure by the Senate the following December.
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The Army-McCarthy hearings. You may have heard of them, may find some of the names vaguely familiar, may dimly recall that one day in school, your teacher spent half an hour on the subject.
The fact is, the hearings were quite a sensation at the time, and they captivated the country in a huge way because of the unprecedented TV coverage.
I was 11 years old in 1954 and had little interest in such stuff. But my parents did. Even though I remember the proceedings on television only vaguely, I have vivid memories of my parents’ reactions to them.
Mom and Dad followed the hearings closely. Mom mostly listened quietly, but Dad regularly got agitated and demonstrative.
He would lean forward in his chair and vigorously yell, ”You son of a bitch!” at the image of Wisconsin Senator Joseph McCarthy on the screen. Dad would huff and fume for a time, then slowly calm down and get absorbed again in the proceedings.
My parents weren’t especially political, but both really disliked McCarthy. They thought he was a charlatan, an opportunistic bully, an embarrassment to the country. To me, he was an obvious blowhard, a pompous jerk.
Once, during one of Dad’s tirades, he said of McCarthy, “No matter what he says or does, nobody can touch him! You can’t fire him!”
He meant, of course, that the senator essentially was untouchable until his next election. But I, being a kid, took Dad to mean that somehow, McCarthy was truly bulletproof, immune from consequences, free to hold Senate hearings to eternity. I marveled at the injustice of it all.
But, as usual, I digress. More to the point, what made the Army-McCarthy hearings such a big deal? I’m glad you asked.
Republican Joseph R. McCarthy was elected to the U.S. Senate from Wisconsin in 1946. By the early 1950s, as the Cold War heated up between the Western powers and the Soviet Union, McCarthy began making a name for himself with vague accusations about insidious communist influences within the U.S. government.
He also branched out into investigations to find and expose homosexuals working in the government, claiming they were vulnerable to communist blackmail and thus were a security risk.
Back then, a certain bonehead element of the populace was stone-cold terrified of communism and, of course, indignantly anti-gay. This is the same bonehead element that today obsesses about immigrants, anchor babies, Sharia Law, and — oh, yes — the existence of gay people.
That element was convinced that communism was a sinister and all-powerful conspiracy intent on enslaving America, blowing us to smithereens with hydrogen bombs, or whatever.
Even at my tender age, I had concluded that the ideology of communism is so dumb and unworkable — so destined to fail — that the best course is to step aside and allow it to collapse.
Had the Western powers simply gone about their business, the people of China and the USSR might have thrown out the Reds themselves. Instead, we freaked out, spent bazillions arming ourselves, and thereby proved the point of the dictators that our side was out to get them.
But I digress again.
McCarthy presented himself as a patriot defending America from the evil Red Menace. He had a knack for using half-truths and innuendo to fuel the fears of the populace, so much so that the terms “McCarthy era” and “McCarthyism” arose.
Wikipedia describes MyCarthyism thusly:
(1) The practice of making unfair allegations or using unfair investigative techniques, especially in order to restrict dissent or political criticism.
(2) Reckless, unsubstantiated accusations, as well as demagogic attacks on the character or patriotism of political adversaries.
The tactics of McCarthy and his cronies are textbook examples of both definitions.
This is how events unfolded…
G. David Schine was the son of a wealthy New York hotel magnate and an ardent anti-communist. In 1952, he published a pamphlet, Definition of Communism, and had it placed in every room of his father’s hotels.
The pamphlet attracted the attention of Roy M. Cohn, McCarthy’s chief counsel. Cohn earlier had helped prosecute Julius and Ethel Rosenberg, who were executed in 1953 for treason and conspiracy to commit espionage. Schine and Cohn, both in their mid-20s, became friends and began working together to save civilization from commies.
Late in 1953, Schine was drafted into the U.S. Army as a private. Immediately, Cohn began lobbying the Army to grant Schine special privileges.
He telephoned numerous officials, from the Army Secretary to Schine’s company commander, asking that Schine be given light duty, be allowed extra leave, and even be made an officer.
The Army told Cohn to stop meddling. Cohn in turn threatened to “wreck the Army.”
As the feud escalated, McCarthy saw an opportunity and joined in. He and Cohn claimed that Schine was in effect being held hostage to stop McCarthy from investigating the Army and exposing communists inside the military.
Neither side would back down, or could, and on April 22, 1954, the hearings of the Subcommittee on Investigations (part of McCarthy’s Government Operations Committee) began.
For its chief counsel, the Army retained Joseph N. Welch, a partner in a distinguished Boston law firm and a magna cum laude graduate of Harvard Law School. As the hearings progressed, McCarthy and Cohn came across on television as angry and harsh; Welch was droll and avuncular and as twinkly as a leprechaun.
For all the theatrics, the outcome was a dud. The committee found that the Army had not been fully cooperative and that Cohn, but not McCarthy, had engaged in “unduly persistent or aggressive efforts” to influence the Army on behalf of Schine.
But by showing McCarthy day after day in an unfavorable light, the hearings significantly damaged his popularity.
At one point in the proceedings, McCarthy barked at Missouri Senator Stuart Symington, “You’re not fooling anyone!”
Symington answered, “Senator, the American people have had a look at you for six weeks. You’re not fooling anyone, either.”
The most memorable moment of the hearings, however, was still ahead.
I will let Wikipedia set the scene:
On June 9, the 30th day of the hearings, Welch challenged Roy Cohn to provide U.S. Attorney General Herbert Brownell Jr. with McCarthy’s list of 130 Communists or subversives in defense plants “before the sun goes down.”
McCarthy stepped in and said that if Welch was so concerned about persons aiding the Communist Party, he should check on a man in his Boston law office named Fred Fisher, who had once belonged to the National Lawyers Guild, which Brownell had called “the legal mouthpiece of the Communist Party.”
Both sides knew that Fisher had belonged to the NLG while in law school. Welch considered it a minor matter from the past, but to avoid trouble, he left Fisher out of the hearings.
When McCarthy attacked Fisher without warning on live television, Welch responded with one of the great put-downs in political history. He told McCarthy:
Until this moment, Senator, I think I have never really gauged your cruelty or your recklessness. Fred Fisher is a young man who went to the Harvard Law School and came into my firm and is starting what looks to be a brilliant career with us.
Little did I dream you could be so reckless and so cruel as to do an injury to that lad. It is true he is still with Hale and Dorr. It is true that he will continue to be with Hale and Dorr. It is, I regret to say, equally true that I fear he shall always bear a scar needlessly inflicted by you.
If it were in my power to forgive you for your reckless cruelty, I would do so. I like to think I am a gentle man, but your forgiveness will have to come from someone other than me.
McCarthy was undeterred and tried to continue, but Welch interrupted him:
Senator, may we not drop this? We know he belonged to the Lawyers Guild. Let us not assassinate this lad further, Senator. You’ve done enough. Have you no sense of decency, sir? At long last, have you left no sense of decency?
When the exchange ended, the audience in the chamber burst into applause.
Lengthy video clips of the encounter are online, but this excerpt will give you the idea.
Before the hearings, McCarthy was viewed favorably by 50 percent of Americans and negatively by 30 percent. After the hearings, the two ratings essentially reversed.
In December 1954, McCarthy was censured by the Senate, for, well, McCarthyism. Although he continued his crusade against suspected communists, many of his fellow senators avoided him, and the press began to ignore him.
His already-heavy drinking increased. He was hospitalized several times for problems related to alcoholism and cirrhosis of the liver. In 1957, at age 48, he died at Bethesda Naval Hospital of liver failure.
After the hearings, Joseph Welch returned to his law firm in Boston. He later narrated the TV shows Omnibus and Dow Hour of Great Mysteries, and he was cast as a judge in the 1959 film Anatomy of a Murder. He said he took the role because “it looked like that was the only way I’d ever get to be a judge.”
In 1960, Welch died of heart failure. He was 69.
After his Army service, G. David Schine returned to his family’s hotel business and later worked as a record and film producer. He married a former Miss Sweden and had five children. In 1996, at age 68, he died in the crash of a private plane in California.
Roy Cohn became a well-known New York defense attorney with connections to city politics. His clients included Donald Trump, assorted Mafia figures, the New York Yankees, and the Archdiocese of New York.
Three times, Cohn was charged by federal investigators with perjury and witness-tampering, but not convicted. In 1986, he was disbarred for unethical and unprofessional conduct, including lying and misappropriating the funds of clients.
He died of AIDS one month later at age 59.
Cohn, who once described gay teachers as “a grave threat to our children,” never admitted to being gay himself. Even at the end, he insisted publicly that he was being treated for liver cancer.
During the Army-McCarthy hearings, there was speculation that Schine and Cohn had a sexual relationship. Cohn denied it, insisting they simply were friends.
Probably, for once, he was being honest.
* DuMont was an early television network that ultimately didn’t make it. The company lasted from 1946 to 1956.

Senator Joseph McCarthy (r) with attorney Roy Cohn.

Army chief counsel Joseph Welch.

Cohn and Schine on the cover of Time Magazine, March 22, 1954.
As a talented writer, your last “picture [of Mr. Colbert with Senators McCarthy and Cruz] is worth a thousand words.”