Washington, D.C. · February 2, 1945

The Combined Chiefs of Staff (CCS) was the supreme mili­tary staff for the West­ern Allies during World War II. CCS members were drawn from the British Chiefs of Staff Com­mit­tee and the Amer­i­can Joint Chiefs of Staff (JCS) and typ­i­cally met in Wash­ing­ton, D.C. On occa­sion Soviet mili­tary offi­cers attended. Meetings took place between Decem­ber 24, 1941, when British Prime Minister Winston Churchill and his mili­tary ad­vis­ers paid their first war­time visit to Wash­ing­ton, and July 26, 1945, when the vic­to­ri­ous Allied heads of state and their mili­tary staffs met in Pots­dam out­side the former Nazi capi­tal, Ber­lin. Between those two dates the full CCS some­times met during the great war­time con­fer­ences such as the one between Churchill and Pre­si­dent Franklin D. Roosevelt in Casa­blan­ca, Morocco, in Janu­ary 1943, when the doctrine of “uncon­ditional sur­render” was announced. The two leaders were deter­mined that the Axis powers would be fought to their ulti­mate defeat, and so preclude Germans from claiming in the future that their country had not been defeated, a claim raised following the Novem­ber 1918 armis­tice that ended World War I.

On this date in 1945 the CSS turned over to the JCS a series of intel­li­gence reports titled “Esti­mate of Soviet Post-war Capa­bil­ities and Inten­tions.” The assess­ments con­cluded that the Soviet Union would seek to con­trol East­ern Europe and influ­ence Central Europe. Already Red Army units occu­pied Roma­nia, Bul­garia, Hun­gary, East Prussia, and Poland, and were within 40 miles of the Nazi capi­tal (see map below). Chillingly, the report pre­dicted that the Soviets would avoid a con­flict with their West­ern part­ners until at least 1952, but that the Soviets would go to war ear­lier if they per­ceived their vital in­terests in Europe were at stake.

That same day Roose­velt and Churchill dis­cussed the CCS report en route to the Crimean resort of Yalta for the duo’s last sum­mit with Soviet dictator Joseph Stalin. (Roose­velt would die in April.) On the final day of their Yalta Con­fer­ence, Febru­ary 11, 1945, the “Big Three” leaders and their mili­tary advi­sers an­nounced agree­ment on the occu­pa­tion of Ger­many and Aus­tria and the divi­sion of Poland, which the Red Army was then emptying of Germans. It would be four and one-half decades—the length of the Cold War—before the Soviet occu­pa­tion of Cen­tral and East­ern Europe ended peacefully with the collapse of the Soviet Union in 1991.

“Big Three” at 1945 Conferences: Yalta and Potsdam

Map of European battlefront, February 1945

Above: The military situation at the end of the Yalta Conference in February 1945. This map is taken from the source “Atlas of the World Battle Fronts in Semimonthly Phases to August 15th 1945: Supplement to the Biennial Report of the Chief of Staff of the United States Army.”

"Big Three", Yalta Conference, February 4–11, 1945"Big Three", Potsdam Conference, July 28 to August 1, 1945

Left: “Big Three” and Western military staff at the Yalta Conference in Soviet Crimea, Febru­ary 4–11, 1945. Seated are Winston Chur­chill (left), Franklin D. Roose­velt, and Joseph Stalin. Standing behind them are British Field Marshal Alan Brooke, Admiral of the Fleet Sir Andrew Cun­ning­ham, Marshal of the RAF Sir Charles Portal (standing behind Chur­chill), U.S. Army Chief of Staff George Marshall, and U.S. Fleet Admiral William D. Leahy (standing behind Roose­velt). The heads of state and their mili­tary advisers announced agree­ment on the military occu­pa­tion of Ger­many and Austria and the divi­sion of a terri­torially adjusted Poland, which after the war was expanded in the west at Ger­many’s expense and shrunk in the east to bene­fit the Soviet Union (the “shrink­age” in the east was Polish ter­ri­tory seized in 1939 by agree­ment with Adolf Hitler in the Molotov-Ribbentrop Nonaggression Pact).

Right: “Big Three” with their principal advisers at the Potsdam Con­ference, July 28 to August 1, 1945. Seated are British Prime Minister Clement Attlee (left), Chur­chill’s succes­sor following British elec­tions in July; U.S. Presi­dent Harry S. Truman, Roose­velt’s succes­sor in April; and Stalin. Standing behind them are Fleet Admiral William D. Leahy, Truman’s Chief of Staff; British Foreign Minister Ernest Bevin; U.S. Secretary of State James F. Byrnes; and Soviet Foreign Minister Vyacheslav Molo­tov. The heads of state and their staffs discussed post­war arrange­ments in Europe, frequently without agree­ment, and future moves in the war against Japan.

Newsreel of Yalta Conference, Where Wartime Allies Drafted Plans for a European Peace