Struik was a steadfast believer in
Marxism. Having joined the
Communist Party of the Netherlands in 1919, he remained a Party member his entire life. When asked in 1994, upon the occasion of his 100th birthday, how he managed to still author
peer-reviewed journal articles at such an advanced age, Struik replied blithely that he had the "3Ms" a man needs to sustain himself: Marriage (although he was recently a widower at that time), Mathematics, and Marxism. During the early 1950s
McCarthy era, Struik's Marxist opinions led to accusations of him being a spy for the
Soviet Union. He was also cited as a "subversive influence in the educational process" in a U.S. Senate committee publication. He denied the allegations, and was called before the
House Un-American Activities Committee (HUAC) on July 24, 1951. Struik refused to answer the more than 200 questions asked of him, repeatedly invoking the
Fifth Amendment's shield against self-incrimination. Soon thereafter, the MIT faculty voted to suspend him, with full salary, until the case was resolved. In April 1953, the head of the MIT mathematics department,
William Ted Martin, testified to the HUAC that he and Struik had both been members of an MIT communist cell between 1938 and 1946. and he was reinstated as a faculty member. He retired from MIT in 1960. == Publications ==