After alerting President Nixon the previous day to the disclosure in the New York Times of secret government documents on the Vietnam War, Deputy National Security Adviser Alexander M. "Al" Haig Jr. briefed Nixon and Secretary of State William P. "Bill" Rogers on the likely identity of the leaker. The source of that information was Walt W. Rostow, a national security adviser in the administration of President Lyndon B. Johnson during the last three years of Johnson's presidency.