Reaction divided along political lines. Murray Kempton, a longtime critic of her sympathy for communist causes, praised her: "It is enough that she has reached into her conscience for an act based on something more than the material or the tactical ... she has chosen to act like a lady." The FBI increased its surveillance of her travel and her mail. In the early 1950s, at the height of anti-communist fervor in the United States, the State Department investigated whether Melby posed a security risk. In April 1952, the department stated its one formal charge against him: "that during the period 1945 to date, you have maintained an association with one, Lillian Hellman, reliably reported to be a member of the Communist Party," based on testimony from unidentified informants. When Melby appeared before the department's Loyalty Security Board, he was not allowed to contest Hellman's Communist Party affiliation or learn who informed against her, but only to present his understanding of her politics and the nature of his relationship with her, including the occasional renewal of their physical relationship. He said he had no plans to renew their friendship, but never promised to avoid contact with her.