Once he was over the trauma of his night on the cliff, Pauling threw himself back into speechmaking. In Washington, D. C., while on a lecture tour, he was approached by a stranger who served him with a subpoena to appear before the United States Senate. The committee requesting his appearance was the Senate Internal Security Subcommittee (SISS), the Senate’s equivalent of HUAC. The purpose was to investigate Pauling’s anti-Bomb petitions -- how they were devised, who gathered signatures, and where the funding came from. The underlying question was: How had Pauling managed to get all those thousands of names without a large -- possibly Communist -- organization behind him?

When he appeared before the committee with his lawyer at his side, Pauling answered all the members’ questions except one: a request to provide the names of everyone who had helped him circulate his petitions. Pauling, after conferring with his lawyer, refused to name names. "The circulation of petitions is an important part of our democratic process," he told the committee. "If it is abolished or inhibited, it would be a step toward a police state. No matter what assurances the subcommittee might give me concerning the use of names, I am convinced the names would be used for reprisals against these enthusiastic, idealistic, high-minded workers for peace." He knew he was risking a citation for contempt of Congress. But he was adamant. He was told in reply that the committee would give him a month to come up with the requested names. The stage was set for a very public fight between Linus Pauling and the United States Senate.