Early on the morning November 13, 1950, Pauling was served with a subpoena requesting him to appear before the California State Investigating Committee on Education. The time for his appearance was set for 10:30 a.m. that same day. Pauling rushed to comply. The committee was holding hearings on the possible effects of loyalty oaths on public school teachers and Pauling figured that he, as a well-known opponent of the oaths, was being asked to provide expert testimony. He did not realize that the committee had been formed out of, chaired by a member of, and counseled by a lawyer for the Tenney Committee. Its purpose was not so much to gather expert testimony as it was to hunt Reds.

For two hours the members questioned Pauling about general political topics, then asked him to come back after lunch. The afternoon session was more personal. They asked Pauling about Sidney Weinbaum, about the groups Pauling supported, about his stumping for Henry Wallace, about his criticism of US government policies. Then, late in the afternoon, came the central question: Are you now a member of the Communist Party? "Well, now, this sounds like an inquiry into my political beliefs," Pauling said. "Of course it is a foolish question, but I suppose it is part of the routine . . . . You never know what you will do until the time arrives for you to do it. I saw man after man, who had spoken strongly against the loyalty oath, sign it when it became evident that he would lost his job if he did not sign it. Now, I feel that the same principle applies here, and I find it hard to decide myself whether to subject myself, perhaps legalistically, just because of a principle, to the difficulties that might arise. Nevertheless, it seems to me that the beliefs that I have about the proper workings of democracy, the way that we can save this nation by preserving democracy against attacks that are being made against it, require that I refuse to answer any question as to my political beliefs and affiliations. And so I say that I shall not answer."

The Committee took a break. When it reconvened, a member reminded Pauling of the legal difficulties that his refusal to answer might present, and tried to get him to reconsider. He refused, and the hearing ended with members of the panel threatening to cite Pauling for contempt. Pauling was shaken by the inquisition. He had seen what had happened to Dalton Trumbo, who was serving a year in the penitentiary for refusing to answer HUAC’s questions while his wife and three children waited. Pauling was not quite sure what to do. The next day he sought advice from a friend on the Caltech faculty, who reminded Pauling that the school’s internal investigation had already discovered that he was no Communist. Why not write President DuBridge a note stating what everyone already knew, that he was not a Communist Party member, and then let DuBridge figure out how to get the information to the committee? The same day, Pauling sent DuBridge a three-page letter including the lines, "I am not a Communist. I have never been a Communist. I have never been involved with the Communist Party." DuBridge made sure it got to the committee. Pauling read it under oath at the next meeting of the investigatory committee, avoiding a contempt charge -- and still managing to maintain his dignity.