Turned the Tide in the Second World War (2013)
First, the Allies needed to win control of the North Atlantic sea-lanes for their convoys. Second, the Allies needed to take control of the skies over West-Central Europe, so Britain would be more than just the launching pad for Operation Overlord, it would be the base of massive destruction from the air. Third, the Allies needed to find a way to get past Axis-held beaches and carry the fight to the heartland of Europe. Fourth, the Allies needed to find a way to counter the Nazi Blitzkrieg, and fifth, the Allies needed to find the best route and methods to take the war to Japan in the Pacific.
In a little more than a year after Casablanca (pictured above, L-R: French General Henri Giraud, FDR, Charles de Gaulle, and Churchill), all of the above was achieved with the exception of the unconditional surrender of the Axis Powers. No straight causal line connects Casablanca to the reality of achieving all five major obstacles to win the war; the Allies were in no position to do anything of substance to pursue Casablanca's goals in early-1942 (actually, WW II deteriorated for the Allies in the months immediately after Casablanca).
Much like Pearl Harbor erased memories of the most divisive period in U.S. History after the Civil War (1938 - 1941; Isolationists v. Internationalists), the ultimate victories in 1945 erased the truth that the Allies were losing World War II by late-1942 / early-1943 . . . the final victories of 1945 obscured how difficult the Allied position was in the middle years of World War II.
From November 1943 to March 1944, there were 16 massive Allied attacks on Berlin. The Allies lost 1047 aircraft, while another 1682 planes were badly damaged . . . attrition was even greater during daytime raids. On 14 October 1943, the ball-bearing factory at Schweinfurt (pinned in the above map) was targeted; 60 of 291 B-17 Flying Fortresses were shot down, and a further 138 damaged. The Allies found out that their theory that "the bomber will always get through" was beyond-wrong. Allied command of the sea-lanes in the North Atlantic and of the air over Western/Central Europe was an illusion . . . both needed to be drastically reversed if there was to be any chance of victory.
Dealing with the Germans on the Atlantic shore was a totally different proposition, as was discovered during the catastrophic Dieppe Raid in Aug 1942 (pinned in the above map) where the majority of Canadians were killed/wounded/captured. The conclusion by the Allies was that it was basically impossible to take a well-defended enemy harbor . . . the strategists started to think about a mass invasion on an open beach, which also seemed impossible. So then, how were the Allies supposed to take the war to Nazi Germany or Imperial Japan with ground troops . . . it definitely seemed like an impossibility by early-1943.
The German military had more-and-better aircraft, tanks, submarines, and on the Eastern Front, the Wehrmacht (the German unified military forces, but often the term refers to the German army) had stopped the Red Army's advance, and were assembling vast forces at Kursk. If Nazi Germany could keep up the momentum in the North Atlantic, blunt the effectiveness of Allied bombing in Europe, and deny the Western Allies any meaningful entry points in France, Stalin may have had no choice but to negotiate separate terms with Hitler, and for the second time in less than thirty years, Russia would have pulled out of a World War.
Systems networks were in play in a military sense, in that successes and failures elsewhere affected other regions/theaters, and the actions of others benefited/cursed others. For example, Stalin benefited tremendously from the Allied bombings in Germany, since Hitler needed to keep military forces in Germany instead of sending them to the Eastern Front. An advantage gained by the Allies in one theater could help campaigns elsewhere, and a serious defeat could damage chances of success in another theater(s).
There was still some work to be done: "Island-Hopping" in the Pacific and continued strategic bombing in Germany, and Japan as well as the advance of the Western Allies to Berlin. True, the Axis Powers overreached in their aggression, and the US especially was able to employ unmatched resources, but HOW did the Allies recover and fight their way to victory during those pivotal 17 months in 1943-1944 . . .