COURTING A RELUCTANT ALLY - National Intelligence University

Operational Intelligence Cooperation—April 1941—November 1941From April 1941 to November 1941, events in the Atlantic clearly indicate thatthe U.S. had abandoned its neutral stance in favor of alliance with Great Britain.As military preparations for this alliance were ongoing, U.S. security interestsprompted Roosevelt to take actions that were decidedly pro-British and, whilesome of these actions met with popular outcry, public opinion was movingtoward Roosevelt’s view. In April 1941, the U.S. began basing forces in Greenland,to aid in the maintenance of security patrols. By this time all U.S. shipsightings of U-boats were passed back to the Admiralty through ALUSNA London.Although this information was not timely, it still assisted the British indeveloping their operational intelligence (OPINTEL) picture and was just the sortof intelligence cooperation they had hoped to obtain from the Americans whenthey first began to press for a closer relationship. 329 In June 1941, Churchillpressed Sir Stewart Menzies to ease the restrictions on the dissemination of U-boat Enigma decrypts and, while the British would be slow to act on this, the U.S.did begin receiving intelligence derived from this source. 330 Additionally, by July1941, the U.S. and the UK routinely shared intelligence derived from HF/DFsites. 331 As the summer progressed, the relationship would become closer still. InJuly 1941, the U.S. would take over the defense of Iceland, relieving Britishforces of the need to perform that duty. During the Atlantic Conference betweenRoosevelt and Churchill in August, one of the substantive agreements reachedwas a policy for the conduct of convoy operations and areas of responsibility forthe two countries, giving further incentive to share intelligence on German navalmovements. U.S. Navy encounters with German U-boats, such as the Greer Incident,inflamed public opinion against the Germans enough that Roosevelt wasable to advise Germany and Italy to keep their warships out of waters under U.S.protection. By the time the Reuben James was torpedoed by a U-boat in lateOctober 1941, Congress was prepared to amend the neutrality laws in ways thatmade the alliance with the British a reality in fact, if not on paper. 332Against this backdrop, two additional visits were made in an effort to furtherincrease intelligence collaboration between the two countries. To reciprocate theSinkov Mission, Commander Alistair Denniston, the Director of GC&CS, visitedthe United States to discuss ways to enhance SIGINT cooperation. Although hisefforts to establish new, official frameworks for collaboration met with no success,the Denniston visit did have a positive outcome. He completely impressed329Smith, Ultra-Magic Deals, 75-76.330Hinsley, British Intel, vol. 2, 55.331Bray, xxi.332Morison, The Battle of the Atlantic, 69-71, 75-76, 78-81.90