The 10 most consequential events of World War II

The virtue of history is that it affords us perspective—not just the distance that the passage of time occasions but the ability to grasp the importance of events that may have been only dimly understood at the time. What might seem of paramount importance to contemporaries may fade into obscurity as the years go by. But war, or at least great wars, may be an exception, and that is certainly true of the conflict that was arguably the biggest turning-point in world history. Suspecting that, I’ve identified the ten most significant events of World War II.

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This post was updated on June 7, 2022.

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This map depicts Operation Barbarossa, the German invasion of the USSR that began on June 22, 1941. It depicts the breadth and complexity of the largest military operation in world history. Note that every one of the tiny rectangles on this map represents hundreds of thousands of soldiers. Image credit: Wikipedia

Gaining perspective on the biggest turning-point in world history

Our view of the most consequential events that took place during the years 1937 to 1945 seems little different from what was understood at the time. Here, in my admittedly unprofessional although informed view, are the ten events that, even today, strike me as having had the greatest consequences for the conduct of World War II.

Month	Year	Event	Description	Initiative
July	1937	Japan invades China	Opening of the Second Sino-Japanese War in Manchuria	Axis
May	1940	Blitzkrieg	Nazi Germany invades France and the Low Countries	Axis
June	1941	Operation Barbarossa	Nazi Germany invades Russia with three million troops	Axis
December	1941	Pearl Harbor	Japan launches war on USA in surprise dawn attack	Axis
December	1941	Battle of Singapore	Japan launches war on British Empire	Axis
June	1942	Battle of Midway	USA defeats Japanese Navy	Allies
February	1943	Battle of Stalingrad	Field Marshal Paulus surrenders Sixth Army to USSR	Allies
May	1943	Battle of the Atlantic	British turn the tide against Nazi Germany’s U-Boats	Allies
June	1944	Operation Overlord	USA and UK invade Normandy	Allies
August	1945	Hiroshima & Nagasaki	USA drops atomic bombs	Allies

Viewed from the perspective of the year 2022, there is remarkable symmetry in this picture. During the war’s first four years, the Axis nations held the initiative. In the following four years, the initiative moved to the Allies. Focusing on one battle, or one theater of the war, can obscure that reality. Some might quibble about the choices I’ve made. Perhaps some other battle might qualify as one of the most significant events of World War II, or one that I’ve picked might seem of less than strategic importance. But the Big Picture is clear.

Revisionist views of the war’s turning points

Admittedly, the chart above reflects the consensus view of historians today. However, there are revisionist views about many aspects of these events.

• For example, it can be plausibly argued that the Soviet Union’s successful defense of Moscow in December 1941 is a more significant turning point in the European war than the victory at Stalingrad. It was then, rather than more than a year later toward the south, that Nazi Germany’s invasion of the USSR ground to a halt. Hitler had made the same catastrophic decision as Napoleon Bonaparte a century and a half earlier—and with the same predictable results.
• Similarly, not all military historians today agree that the Battle of Midway was the turning point in the Pacific. That assertion reflects the naval strategy advanced by Admiral Chester Nimitz. Some observers argue that the Battle of Guadacanal months later was more decisive, as General Douglas MacArthur might have insisted. The two co-equal commanders in the Pacific war were rivals throughout and continue to have their champions. Yet others might plausibly contend that the die was cast for Japan’s defeat as soon as her navy attacked Pearl Harbor. As Admiral Yamamoto himself fully understood, there was no chance that the Japanese Empire could prevail in the long war with the United States that the attack itself ensured.
• The conventional view is that the Japanese Empire consented to unconditional surrender because of the two nuclear weapons dropped on Hiroshima and Nagasaki, and there is of course no doubt that was a meaningful factor in the decision. However, many have argued persuasively that the declaration of war on Japan by the Soviet Union on August 8, 1945, weighed even more heavily on Emperor Hirohito and his Cabinet.

Critical advances in science and technology

However, it’s difficult to appreciate fully the Big Picture without noting the advances in science and technology and in industrial production that loom large in the story of the war, too. Any full account of World War II is incomplete without knowledge of the development of radar and the atomic bomb, and the success in breaking the German Enigma system and the Japanese codes dubbed Magic and Purple by the Allies, as well as other significant Axis codes and ciphers. Equally, perhaps even more important, were the breakthroughs in industrial organization that enabled the United States to produce hundreds of thousands of airplanes, ships, and tanks in record time.

Political events had vast consequences, too

All the ten events I’ve listed above involve military conflict. Some might plausibly argue that several political events should be given equal standing.

• Neville Chamberlain’s surrender at Munich in 1938, for example.
• The Nazi-Soviet Nonaggression Pact in 1939.
• Winston Churchill‘s appointment as Prime Minister in 1940.
• The 1940 reelection of Franklin Delano Roosevelt. Leadership matters, and never more so than in war.
• British interference in American politics in 1940 and 41 that paved the way for America’s entry into World War II.
• Adolf Hitler’s declaration of war against the United States following Pearl Harbor—even though FDR had pointedly refrained from provoking him by including Germany when he asked Congress to go to war against Japan

However, it’s challenging at best to compare the consequences of these undoubtedly important events with campaigns and battles that together claimed many millions of lives. It’s those blood-soaked episodes that I believe are the ten most consequential events of World War II.

Books to read

Over the years, especially during the past decade, I’ve read a great deal about World War II. If you’re interested in exploring any aspect of this world-shaking contest, you might turn to any of the following posts. Together, these articles survey scores of books that I found rewarding. (Those I didn’t enjoy either fell by the wayside, unfinished, or I simply didn’t include their reviews in these lists.)

• 5 top nonfiction books about World War II
• The 10 best novels about World War II
• 15 good books about the Holocaust, including both fiction and nonfiction

However, if some other topic or genre strikes your fancy, you can always find my most popular reviews, and the most recent ones, plus a guide to this whole site, on the Home Page.