Crossing Army Chief of Staff Gen. George C. Marshall was never a good move. Though his reputation for integrity and impartiality earned him the respect of people in power, what most didn’t know was that Marshall had a vindictive streak; he neither forgot nor forgave. In early 1942, Marshall visited Prime Minister Winston Churchill and the Imperial General Staff to explain Operations Roundup and Sledgehammer, and get their agreement for these proposed landings in France in 1943. When Marshall left England, he erroneously thought he had it. When the British torpedoed both plans weeks later, Maj. Gen. Hastings “Pug” Ismay of the Imperial General Staff noted that American reaction was “that we had broken faith with them.” British lack of candor with Marshall now came home to roost as the Combined Chiefs of Staff prepared to meet at Château Frontenac in Quebec, Canada, in the strategic war conference code-named Quadrant.

Quadrant. Of all the strategic war conferences held during World War II, few were more contentious than Quadrant, the only conference in which shots were fired (though not in anger). While Quadrant had to unexpectedly and urgently tackle the surrender of Italy and settle offensive operations against Japan, top on Quadrant’s agenda was the cross-channel invasion now code-named Overlord.

“In addition Marshall still feels injured that we turned down his plans for cross channel operations last year. I am not looking forward to this coming meeting, and feel we shall have a very difficult time.”

– Gen. Sir Alan Brooke, Aug. 11, 1943, diary entry

Overlord may have been the topic on the table, but the real issue was the strategy differences between America and Britain that came to a head at Quadrant. Marshall was the acknowledged leader of the American position: a direct assault on Germany with a landing in France. The British, led by Churchill and haunted by the bloody ghosts of the Somme and Passchendaele, advocated a peripheral strategy. Quadrant thus became a showdown between Marshall and Churchill, primarily through Chief of the Imperial General Staff Gen. Sir Alan Brooke.

Though obviously biased, Brooke’s War Diaries 1939-1945 provides a blunt account of what happened. Phrases like “we were not trusting each other,” “painful meeting,” “settled nothing,” “quite impossible to argue with [Marshall],” and other such comments are scattered throughout his entries.

Churchill tried to cloak the peripheral strategy under the guise of a “purely opportunistic strategy” that allocated additional forces in the Mediterranean to exploit the political situation in Italy, secure the Dodecanese Islands off the coast of Turkey in the east (in order to bring that neutral country into the Allied camp), and an invasion of the Balkans (to forestall Soviet ambitions). Then, on the other end of the continent, he held out for an invasion of Norway. Churchill’s restless and perfervid mind also insisted that within the campaign against Japan an invasion of Sumatra be included.

When things got to loggerheads on Aug. 15, the second day of the conference, Marshall played his most powerful trump: Unless the British gave Overlord priority, the Americans would shift from the existing “Germany First” strategy to a “Japan First” strategy. As U.S. Navy Chief of Naval Operations Adm. Ernest J. King, the American public, and Gen. Douglas MacArthur, supreme commander of the Southwest Pacific Theater, favored “Japan First,” Brooke dared not gamble that Marshall was bluffing.

Churchill’s barrage of alternative campaigns that drove Brooke to distraction and alarmed the Americans was possibly also an expression of growing frustration by a brilliant, strong-willed individual fighting vainly to retain eroding power. That was the rub. In 1943, American industrial output and military might was on the rise and Britain’s was on the decline. Because the United States would have a preponderance of forces in Overlord, at Quadrant, President Franklin D. Roosevelt and Churchill agreed command of the assault would go to an American, presumably Marshall, a position originally promised by Churchill to Brooke.

Prior to Quadrant, on July 25, Marshall received Roosevelt’s “whole hog” backing for Overlord to the point where the president said if the British scanted on it, the Americans should go it alone. Acknowledging the opportunity presented by Mussolini’s downfall, Marshall agreed to an increased commitment in Italy. Otherwise, he stood firm. When things got to loggerheads on Aug. 15, the second day of the conference, Marshall played his most powerful trump: Unless the British gave Overlord priority, the Americans would shift from the existing “Germany First” strategy to a “Japan First” strategy. As U.S. Navy Chief of Naval Operations Adm. Ernest J. King, the American public, and Gen. Douglas MacArthur, supreme commander of the Southwest Pacific Theater, favored “Japan First,” Brooke dared not gamble that Marshall was bluffing.

A moment of unintended levity occurred when Vice Adm. Louis Mountbatten gave a demonstration of his Habakkuk Project, the proposed building of unsinkable aircraft carriers constructed out of Pykrete, a compound composed primarily of ice and wood shavings. The demonstration included Mountbatten firing a pistol at a block of ice (which shattered) and a block of Pykrete (which did not). The bullet is said to have ricocheted off the impervious Pykrete, nicking King’s leg.

When Quadrant ended on Aug. 24, Marshall had won. Overlord had a landing date (May 1, 1944) and priority in troops and materials. Like a worm on a fisherman’s hook, in the months to come, Churchill repeatedly tried to wriggle out of Overlord’s priority commitment, but Marshall made sure he didn’t.