In the late 1940s and into the mid-1950s, Senator Joseph R. McCarthy of Wisconsin ran an unsubstantiated and divisive campaign of deceit and distrust that shook the nation to its core.

It came to a head 67 years ago this month, when McCarthy accused the United States Army of being infiltrated by communists, and ran up against a lawyer who brought him crashing down in a heap of humiliation.

The background: Congress created the House Un-American Activities Committee (HUAC) in 1938 to investigate communist and fascist groups that organized during the Great Depression.

Following World War II, the HUAC gained convictions against accused spy Alger Hiss in 1948, a year after 10 Hollywood writers and directors who spoke out against the committee’s tactics went to prison on contempt of Congress charges. They were blacklisted from working in Hollywood again upon their releases.

Meanwhile, the Cold War had ramped up with Germany split in two, including dividing the city of Berlin after the war. The Soviets had imposed socialism on East Germany while the Allies brought democracy to West Germany and West Berlin. In southern Asia, communists had taken control in China, creating the People’s Republic of China.

Supported by the Soviets, North Korean forces crossed the 38^th Parallel to invade South Korea in 1950, starting the Korean War. The United States backed South Korea. China soon joined in, backing North Korea. Cold War tensions suddenly turned deadly.

McCarthy effectively used the Cold War to instill suspicion that communists had infiltrated many elements of American government, politics, and life in general. He once held up a document bearing the names of 205 State Department officials he claimed were known to be members of the Communist Party.

A subsequent investigation turned up no such evidence. Even so, McCarthy held so much power – through fear and intimidation – that Congress overrode President Truman’s veto of the 1950 McCarran Internal Security Act that essentially gave the government the ability to impose its will against so-called “subversives.”

In 1953, McCarthy gained control of the Committee on Government Operations, which gave him an even freer hand in spewing his distortions and vitriol.

McCarthy, though, could not control the free press; specifically, CBS reporter Edward R. Murrow, who steadfastly debunked and discredited McCarthy and his manipulation of the facts.

Even so, it took a huge – no, make that monumental – misplay to bring him down. Actually, McCarthy made two mistakes. He allowed hearings in 1954 to be televised live. The entire nation got to witness his behavior, heard him claim that communists had infiltrated the Army, and listened as he yelled angrily at witnesses.

And during these hearings, McCarthy met his match in Joseph Welch, a calm but assertive special counsel representing the Army. On June 9, 1954, Welch calmly gutted every one of McCarthy’s accusations, frustrating the senator to no end.

McCarthy called one highly respected and decorated general a “disgrace” to the uniform; and then accused one of Welch’s associates of belonging to a group that was the “legal arm of the Communist Party.”

Welch reached his breaking point and uttered the words that in essence ended McCarthy’s reign of terror.

“Until this moment, Senator, I think I never really gauged your cruelty or your recklessness,” Welch said. “Have you no sense of decency, sir?”

The audience roared and applauded. It ushered in the beginning of the end for the bully McCarthy, soon to be censured by the same Senators who, to that point, had lacked the guts to stop him.

He died in 1957. HUAC became the Committee on Internal Security in 1969, Congress disbanded it completely six years later.