Why did Linus Pauling appear before a congressional subcommittee in 1960?

In 1960, Linus Pauling appeared before a congressional subcommittee to defend his activities regarding a crusade to stop the atmospheric testing of nuclear weapons.1

During this period, Pauling had become a prominent advocate for a test ban, notably presenting an appeal to the United Nations in 1958 signed by over 9,000 scientists. When questioned by the subcommittee, Pauling refused to reveal the names of the individuals who had assisted him in collecting those signatures. By taking this principled stand to protect the identities of his collaborators, he risked imprisonment—an action that was initially condemned but later earned him widespread admiration. His persistent efforts in this cause were eventually recognized with the 1962 Nobel Prize for Peace.12