We go to war with the U.S.S.R. dun dun dun...
Patton is right and convinces Allied High Command that the Soviets are a far worse threat than the Germans ever were.
Unlike the Luftwaffe, we have bombers with the range to hit Soviet factories in/behind the Urals and unfortunately for the Soviets we cut off all lend/lease shipments. With Soviet aircraft designed to fly at lower altitudes the bomber streams hit Soviet cities and factories with impunity.
Mustangs, followed by first generation jets rule the skies over the Soviet Union.
The Soviets pay for their recklessness in sending units into a meatgrinder offensive vs Germany with a seriously depleted manpower base and can't keep up the war of attrition. Without the American lend/lease trucks (and spare parts for them) the Red Army suffers logistics problems. Swarms of Allied fighter/bombers wreak havoc on Soviet ground units. Lines/pockets of resistance are quickly smashed with artillery and air attacks.
Patton, pissed off that he doesn't get to attack Moscow, races to the Volga and takes Stalingrad, a feat the Germans failed to accomplish. Still angry that Bradley was given Moscow as his objective, Patton turns his 3rd Army north against orders and starts driving to Moscow, determined to repeat his success in Sicily.
Montgomery, still leading the British forces takes Leningrad but only with heavy losses.
Bradley's army's offensive stalls and Eisenhower finally gives Patton the green light he has wanted all along and supplies are diverted to his 3rd Army. The 4th Armored and 87th Infantry spearhead the capture of Moscow and the Kremlin. Stalin and the Politburo have fled. The Soviet Union has fallen and untold millions are spared unspeakable suffering behind the Iron Curtain.
Superior Allied tactics, equipment, planning, leadership and individual initiative won freedom for millions that didn't have it before.
I apologize for the rough draft but it was the best I could come up with on such short notice.