[4][7] Angered by what he perceived as the judicial mistreatment and illegal execution of the anarchists Sacco and Vanzetti in 1927, he drove a taxi cab for two years to earn money for law school.

[12][13] Pressman said the men merely met to study and discuss left-wing political theory, but Chambers described it as a Soviet-controlled cell dedicated to committing espionage.

Historian Arthur M. Schlesinger, Jr. observed that Chambers never provided evidence of Witt's party membership, just uncorroborated accusation.

[19] There is general agreement among professional historians that Witt's communist views did not affect his work and did not change the outcome of any policy choices made by government agencies.

[11] Witt was named Secretary (the highest non-appointed bureaucratic office—or "the top administrative officer"[1]) of the Board in October (or November[1]) 1937.

[11] The enormous workload and tremendous expansion in the number of personnel at the NLRB made Witt the agency's most powerful individual.

[26] By September 1940, the Smith Committee was accusing other NLRB employees, such as chief economist David J. Saposs, of harboring communist ideas.

President Franklin D. Roosevelt named University of Chicago economics professor Harry A. Millis to be the new chairman of the NLRB in November 1940, after Madden's term on the Board expired in August.

[34] He briefly served as legal counsel to the International Fur & Leather Workers Union in 1944 in a major due process case.

"[38] Also in early 1948, Witt was working with fellow National Lawyers Guild member Joseph Forer of Washington, DC.

On January 26–28 and February 2, 1948, a hearing of the House Education and Labor Subcommittee, chaired by U.S. Representative Clare E. Hoffman, occurred on the topic of a strike by United Cafeteria and Restaurant Workers (Local 471) and its parent, the United Public Workers of America (UPWA), CIO, against Government Services, Inc. (GSI), which had already lasted nearly a month.

[42] In 1950, the U.S. State Department revoked singer and civil rights activist Paul Robeson's passport as a means of preventing him from traveling overseas and continuing his left-wing political work.

[2][45] He had a close connection to Albert Pezzati, who had been eastern regional director, national board member[46][47] and secretary-treasurer[48] of the International Union of Mine, Mill and Smelter Workers.

[49]) In 1961, Witt and Joseph Forer represented the International Union of Mine, Mill and Smelter Workers in Robert F. Kennedy, Attorney General of the United States, Petitioner, v. International Union of Mine, Mill and Smelter Workers, Respondent before the Subversive Activities Control Board.

[2] On August 3, 1948, in testimony to the House Un-American Activities Committee (HUAC), Whittaker Chambers named Witt as a member (and even leader[1]) of the "Ware Group.

"[51] When called before a one-man subcommittee of HUAC (whose sole member was Representative Richard Nixon) on August 20, Witt denied knowing "J. Peters" (ostensibly the head of the Soviet Union's political operations in the United States), Chambers, or Alger Hiss.

[52] Along with Abt and Pressman (with Cammer as legal counsel for all three[1]), Witt invoked First, Fifth, and Sixth Amendment rights when refusing to answer HUAC questions.

[52] Lee Pressman, also testifying that day, forced the subcommittee to admit that it was not accusing the men of espionage but rather being communists seeking to infiltrate the government (which was not a crime).

[52] A few weeks later, former Daily Worker editor turned anti-communist Louis F. Budenz testified that the CPUSA considered Witt a member.

[53] Federal law enforcement officials debated prosecuting Witt in late 1948—not for being a communist, a spy, or for committing espionage, but under a contempt of Congress charge for asserting his Fifth Amendment rights before the committee and refusing to answer its questions.

Having refused to answer questions before Congress, "Witt understood that the public saw that as tantamount to admitting guilt" to Communist activities.

"[56] Speaking before a HUAC subcommittee on September 1, Witt once more denied that he had engaged in espionage, again invoked his Fifth Amendment privileges when asked about his CPUSA and "Ware group" membership, and refused to say whether he knew Chambers, Bentley, or scores of others.

[57] In February 1952, writer Nathaniel Weyl named Witt as a "Ware group" member before the United States Senate Subcommittee on Internal Security.

In April 1955, the Subcommittee on Internal Security learned that Witt had obtained a cash donation from the Mine, Mill and Smelter Workers Union to help Matusow get his book published.

For instance, he noted how a New York Journal-American story led a story stating "The government ended its cross-examination of Alger Hiss at 3:01 p.m. today after forcing him to admit he was an associate of Mrs. Carol King, prominent legal defender of Communists, and a friend of Nathan Witt, ex-New Deal lawyer who was fired because of his Communist activities."

He also noted the guilt by association tactics of fellow journalists, for example, Westbrook Pegler, who sought to discredit Eleanor Roosevelt through link to Hiss via Felix Frankfurter.

In 1977 during an interview, David A. Morse (1907–1990), recounted that in 1949, shortly after he had finished work as NLRB general counsel and become a US delegate to the International Labor Conference of the International Labour Organization (ILO): At about that time, I think there were all these questions being raised about certain people in the Labor Board; not so much about their qualifications as their political orientation and what Paul Herzog wrote there may have been as a result of that.