The Senate shed light on one of its darkest moments in history Monday, making public the transcripts of Sen. Joseph McCarthy’s (R-Wis.) closed-door interrogations of 500 people, part of his Cold War-era quest to root out communism in the U.S. government.

Marking the 50th anniversary of the McCarthy hearings, the Governmental Affairs permanent subcommittee on investigations released 5,000 pages of never-before-seen secret testimonies in a five-volume set covering hearings convened in Washington, D.C., Massachusetts, New Jersey and New York. In many cases, these private hearings served as a warm-up for the Wisconsin Republican’s notorious public hearings on communist infiltration of the U.S. government that captivated the nation in 1953 and 1954.

[IMGCAP(1)] McCarthy’s investigation was judged a miserable failure, with not one witness being sent to prison based upon information dug up by the Wisconsin Senator and his staff.

In fact, his colleagues found his conduct during the investigation to be an embarrassment to the Senate, and censured him Dec. 2, 1954, for acting in a way “contrary to Senatorial traditions.” But not before he ruined the lives and careers of scores of people. McCarthy is also blamed for the death of a Voice of America employee, Raymond Kaplan, who so feared being called to testify before the subcommittee, he chose instead to take his own life by hurling himself in front of a moving truck on March 5, 1953.

“Senator McCarthy’s zeal to uncover subversion and espionage led to disturbing excesses,” Sens. Susan Collins (R-Maine) and Carl Levin (D-Mich.) wrote in a somber preface to the report. “His browbeating tactics destroyed careers of people who were not involved in the infiltration of our government.”

“These hearings are a part of our national past that we can neither afford to forget nor permit to reoccur,” wrote Collins and Levin, who served as the subcommittee’s ranking Republican and Democrat in the 107th Congress, when the decision was made to open the transcripts.

The transcripts show that McCarthy was just as ruthless in his questioning of witnesses behind closed doors as he was when the television cameras and nation’s newspapers provided him the national stage in his very public hunt for Communists. Most of the people called to testify before his subcommittee were government workers, but well-known luminaries such as poet Langston Hughes and James Reston, the New York Times Washington bureau chief, were also summoned before the panel.

The release of the testimonies is considered to be a gold mine for McCarthy scholars, who are forbidden to review the Senator’s personal papers housed at Marquette University. Those papers are sealed for the life of McCarthy’s adopted daughter.

“We will have a much more authoritative sense of what McCarthy was doing,” said Associate Senate Historian Don Ritchie, who edited the transcripts. “What he knew. What he didn’t know and how valid his charges were or how grossly exaggerated his charges were.”

Ritchie said that from his review of the testimony over the past two years he “can’t see people getting a positive image of McCarthy from this,” and he offered an equally stinging critique of Roy Cohn, the Senator’s top aide on the subcommittee.

“They badgered the witnesses — they twisted the witnesses’ words around against them — they exaggerated the case against them,” Ritchie said. “It is very hard to read these transcripts without noticing that.”

Ritchie described Cohn as a “26-year-old counsel who is out to make a name for himself and brings out all the worst in McCarthy.

“If McCarthy had a more mature chief counsel, somebody with a little more savvy, a little more experience and a little more sense of balance, then the hearings might not have become as controversial and outrageous as they were,” Ritchie said.

Still, McCarthy played hardball behind closed doors, in one instance forcing a gay witness to out another gay man once employed by the federal government. In another case, McCarthy tried to pressure a witness into disclosing his mother to be active Communist.

Ritchie said the witnesses who refused to cave into McCarthy’s pressure tactics in the closed executive sessions in many cases were not called to testify in public.

“The people who were able to defend themselves and stood their ground and articulated their positions, McCarthy wasn’t interested in having them do that in the public arena,” Ritchie said. “The people who either kowtowed to him or stonewalled him by taking the Fifth Amendment, they were the ones he preferred to call into the public hearings. That would create a confrontational situation.”

McCarthy’s effort to launch an investigation into communist subversion was originally accepted by his Congressional colleagues, but the inquiry soon spiraled out of control, leading the three Democrats on the seven-member subcommittee to resign their seats in July 1953. They did not return to the subcommittee until January 1954.

And Robert Kennedy, who briefly worked for McCarthy, resigned his post “after literally coming to blows with Roy Cohn — telling the chairman [McCarthy], that the subcommittee was ‘heading for disaster,’” Ritchie writes in the introduction of Volume One. Kennedy would return in 1954 as the Democratic counsel for the subcommittee.

In many instances, McCarthy would announce hearings with little notice or wait until the last minute to tell his colleagues he had scheduled a session outside D.C., making it difficult for other Senators to attend. The absence of other lawmakers allowed McCarthy and Cohn to run the hearings as they pleased; it was in these instances that their witness intimidation tactics were often used.

As a result of McCarthy’s actions during his pursuit of Communists, the Senate was forced to review its rules, resulting in a change in how investigations could be conducted and witnesses treated.