[1][2] In January of 1942, five weeks after the Japanese attack on Pearl Harbor, Secretary of War Henry Stimson tapped McCormack to head up a new intelligence branch whose central purpose was to collect, digest, and swiftly disseminate deciphered code messages from the enemy, principally Germany and Japan.
Stimson was convinced that all of the necessary information to anticipate, and even prevent, the attack on Pearl Harbor had been in American hands, but that the military intelligence system had failed to analyze or use it properly.
By mid-March 1942, McCormack's new operation is churning out a daily Summary for the Chief of Staff that contains complex information written clearly in grammatical English.
Reading them carefully gives one a sense of viewing World War II through the eyes of the Foreign Minister of Japan.
(As part of the 1943 BRUSA Agreement, McCormack, Colonel Telford Taylor of Military Intelligence, and Lieutenant Colonel William Friedman visited Bletchley Park in April 1943, where they worked with Commander Edward Travis (RN), head of the British communications intelligence (COMINT) facility, and shared their solution to the Japanese Purple machine.
He concluded that was not the case, but considerable ill feeling had been aroused (Churchill had told Roosevelt in February 1942 that he had stopped British work on American diplomatic codes, a warning to tighten them up).
[citation needed] McCormack resigned on April 23, 1946, in a memo to Dean Acheson, then acting Secretary of State, with the following explanation: The series of Departmental Orders issued yesterday, relating to the intelligence organization within the Department, provide for dismembering the Office of Research and Intelligence and transferring its functions to a group of separate research divisions under the Political Offices, and they contain other organizational provisions that I regard as unworkable and unsound.
[6]In its obituary, the New York Times later stated that McCormack had resigned in October 1946 "after a sharp difference in opinion over the organization of the department's intelligence functions.