What information does Herbert Gelman reveal about Leffingwell in the novel, Advise and Consent?

Herbert Gelman, a longtime associate of Leffingwell, reveals to the subcommittee –and the country and the world at large –that he and Leffingwell were once part of a Communist cell. Gelman is currently employed by the Commerce Department of the Bureau of International Economic Affairs. Gelman briefly flirted with a Communist group while in college, ultimately rejecting the philosophy. This is why he goes public against Leffingwell. Leffingwell attempts to cast doubt on Gelman’s reliability given that Gelman has suffered nervous breakdowns, but Gelman’s reliability holds up. Gelman is based on Whittaker Chambers, a real-life reformed Communist who exposed Alger Hiss.