By early 1942, the Allies were grappling with formulating a coordinated strategy against the Axis powers. The American and British leaders, President Franklin D. Roosevelt and Prime Minister Winston Churchill, held a series of conferences year-round to chart the war's course. While defeating Germany retained priority, disagreements arose regarding the most effective approach. Utilizing their expanding industrial and military might, the American military under General Dwight D. Eisenhower, called for a direct attack on Germany through France. They envisioned a large-scale landing operation codenamed "Operation Roundup," that would strike a decisive blow against the heart of German power.
However, the British, under the cautious General Bernard Montgomery, favored an indirect approach. They argued that invading peripheral areas like North Africa and the Mediterranean would wear down the already overextended German military and foment resistance movements in occupied territories. Moreover, this expedition would also offer important battle experience for the ultimate objective of invading Axis-held parts of Europe before the invasion of Nazi Germany was to commence. Additionally, focus on the Mediterranean and North Africa was emphasized. This move prioritized seamless supply lines and communications with Commonwealth forces belonging to Australia, New Zealand, Canada, and India, who were also involved in the war in North Africa. Eventually, the Americans agreed to a compromise and postponed Operation Roundup to focus on driving the Axis out of North Africa. Instead of their earlier plans, Operation Torch, an alternative strategy commenced. Interestingly, this would also be the United States' first military victory in World War II.
By November 1941, an Allied counterattack to regain positions lost to the Axis was already underway; however, a German counter-offensive reversed the Allied gains, too. The situation in North Africa continued to remain precarious. Erwin Rommel, a capable German Field Marshal popularly known as the "Desert Fox," led early German offensives that drove British forces back to Egypt. By early 1942, the Allies were already repulsed and retreated into Egypt. The Axis forces pressed on regardless and were stopped only following the First Battle of El Alamein.
The Axis powers would attack El Alamein once more but were defeated again. Luckily for the Allies, General Montgomery's successful counteroffensive—Operation Crusader—changed the war's course by November 1942. This operation reflected superior planning and tactical maneuvering, inflicting heavy losses on Rommel's forces and enabled the Allies to reclaim all lost ground. In the Second Battle of El Alamein, the Allies went on the offensive and dislodged the Axis from their recent gains. Subsequently, the Axis forces were pushed back beyond Libya into Tunisia, effectively defeating them in a vast swathe of North Africa. The naval landings of British and American forces in Vichy-held French North Africa in November 1942 also supported these offensives. Retaliating against the switching loyalties of French-held North African colonies, Hitler called for an invasion of Vichy France, which went unresisted. However, the French fleet was sent away to avoid Axis capture.
The Axis, who were holding out in Tunisia, would suffer defeat there, too. By May 1943, the Axis forces in the region were dislodged just as they had in the nations eastward. These victories in North Africa would bolster Allied supply lines and communications with their Asian allies and colonies, paving the way for stable fronts that would become the launching pads for a future invasion of the Italian peninsula. It's crucial to remember that the German Navy, which still exercised considerable influence in the seas, continued to harass the shipping lanes in the Atlantic. This would change soon, however, with the American and Royal Navies effectively countering German U-boats and inflicting heavy losses on German fleets. The victory in North Africa further aided Allied naval prowess and the ability to maintain shipping lanes and counter the Axis’ thalassocratic sway.
Despite facing significant losses from a resurgent USSR on the Eastern Front, German forces held onto their territorial gains from the previous year. However, their ambitious summer offensive in 1942, or Operation Blau, aimed at capturing the Soviet oil fields in the Caucasus and crippling the Soviet war effort. Regardless, this proved disastrous for the Germans. The operation would last from June until November 1942 and culminate in complete operational failure for the Axis powers. To thwart German advances, the Soviet Union under Joseph Stalin adopted a scorched-earth policy that involved burning crops and destroying infrastructure. The harsh winter further hampered the German offensive, with troops suffering from inadequate supplies and freezing temperatures. There were some failures for the USSR as well, with the Germans blunting the Soviet advances in Kharkiv and the Kerch regions.
The turning point on the Eastern Front came at the Battle of Stalingrad, commencing in July 1942. The Germans, determined to capture the strategically important city, engaged in brutal urban warfare with the Red Army. With intense and relentless fighting, both sides suffered heavy casualties. However, the Soviets refused to yield. In November 1942, with the Nazi forces stretched thin and facing encirclement, the Soviets launched a massive counteroffensive called Operation Uranus. They succeeded in encircling the German Sixth Army within Stalingrad, trapping over 300,000 soldiers.
Despite desperate attempts to break free, the Germans faced relentless attacks and dwindling resources. By February 1943, the remaining German troops in Stalingrad had surrendered, marking a major Soviet victory and a significant turning point in the war. The Battle of Stalingrad is considered one of the bloodiest battles in history, with an estimated total of over 2 million casualties. The Soviet victory at Stalingrad set the stage for the forthcoming counter-offensives from Russia, eventually leading to the invasion of Axis allies in the vicinity. This culminated in the invasion of Germany itself a couple of years later.
In the Pacific, the Japanese made many swift gains in Burma, Dutch Indochina, Malaya, and Singapore. The Japanese expedition to the Philippines was also successful, with the local forces and the American military facing defeat. While the United States carried out the Doolittle Raid, it led to only a few operational achievements and instead galvanized the Japanese forces to capture Midway Atoll to cut off communication lines between the American and Commonwealth forces. However, the pivotal Battle of Midway in June 1942 inflicted a crippling blow on the Japanese Navy, shattering their offensive momentum. The Allies, adopting an "island hopping" plan, gradually captured strategically important islands throughout the Pacific, bypassing heavily fortified Japanese strongholds and isolating them from resupply routes. This approach, while slow and methodical, aimed to weaken Japanese defenses and secure airbases closer to the Japanese mainland.
In May 1943, the Allies launched Operation Cartwheel, a major offensive aimed at capturing key Japanese bases in the Solomon Islands and New Guinea. This campaign involved numerous brutal land battles, including the protracted and costly Battle of Guadalcanal, which lasted for six months and ended in a decisive Allied victory in February 1943. The success of Operation Cartwheel significantly weakened Japanese control of the central Pacific and opened the pathway for further Allied advances. This theater was the site of several naval confrontations and involved significant carrier groups and fleets of both the United States and the Japanese Imperial Navies.