The Second World War did not begin by accident. It was the deliberate project of one man who had spent nearly two decades preparing for it.
Adolf Hitler did not stumble into the conflict that consumed over 70 million lives. He drove toward it methodically, removing every obstacle between Germany and total war.
The statesmen who tried to stop him, the generals who doubted him, and the nations that thought they could contain him all underestimated the same thing: the depth of his conviction that war was necessary, desirable, and ordained.
To understand why, the story must begin 20 years before the first shots were fired.
On June 28, 1919, inside the Hall of Mirrors at the Palace of Versailles, German representatives signed the treaty that would define European politics for two decades. They had no choice. If they refused, the Allied blockade would continue and the armistice would be cancelled.
The Treaty of Versailles was one of the most punishing peace settlements in modern history. Under Article 231, the infamous war guilt clause, Germany accepted sole responsibility for the war.
For millions of Germans who believed their country had fought a defensive war, this was a civilizational humiliation. It became the foundational grievance of the Weimar Republic.
The territorial provisions stripped Germany of roughly 13 percent of its pre-war territory and 10 percent of its population. Alsace-Lorraine returned to France. The Rhineland was to be occupied for 15 years and permanently demilitarized.
In the east, the new state of Poland received a corridor to the Baltic Sea, cutting off East Prussia from the rest of Germany. The port city of Danzig became a free city under League of Nations protection.
Germany lost all its overseas colonies. The army was reduced to 100,000 men, the general staff abolished, and tanks, military aircraft, submarines, and heavy artillery forbidden.
Reparations were eventually fixed in 1921 at 132 billion gold marks, an amount even Allied economists knew Germany could never fully repay.
What the peacemakers created was a resentment engine. As French Marshal Ferdinand Foch reportedly said, it was not peace but an armistice for 20 years. It was exactly 20 years and 65 days from the treaty's signing to the German invasion of Poland.
Hitler understood this resentment because he shared it personally. He had served as a corporal, was wounded, and was temporarily blinded in a British gas attack in October 1918. He called Germany's surrender the worst day of his life.
For Hitler, Versailles was not a diplomatic settlement but a declaration of war against the German people. His entire political career was directed toward its destruction.
The stab-in-the-back myth, known in German as the Dolchstosslegende, was the lie that made Nazism possible. It claimed Germany had not been defeated on the battlefield but betrayed by Jews, Marxists, pacifists, and socialists at home.
The myth was amplified in 1919 when General Erich Ludendorff told a Reichstag committee that defeat came from domestic subversion. The irony was staggering: Ludendorff himself had demanded the armistice in September 1918 because the military situation was hopeless.
The betrayal narrative preserved German dignity and needed culprits. It pointed to Jews, drawing on centuries of anti-Semitic prejudice. Hitler absorbed this conspiracy theory and treated it as historical fact for the rest of his life.
For Hitler, undoing Versailles was a sacred obligation. Every step, from the reoccupation of the Rhineland to the invasion of Poland, was part of restoring German dignity and power.
But the roots of his drive to war went deeper than Versailles. They reached into an ideological system so radical that no revision of a peace treaty could satisfy it.
Adolf Hitler was born on April 20, 1889, in Braunau am Inn, on the border between Austria and Bavaria. His father, Alois, was a customs official who was authoritarian and frequently brutal. His mother, Klara, died of breast cancer in 1907, devastating the 18-year-old Hitler.
In 1907, Hitler applied to the Vienna Academy of Fine Arts and was rejected. He applied again in 1908 and was rejected a second time. He spent the next five years in Vienna in deepening poverty.
It was in Vienna that his anti-Semitism crystallized from vague prejudice into consuming obsession. He absorbed the virulent politics of Mayor Karl Lueger and the pseudoscientific racial theories that were mainstream in early 20th-century Europe.
Thinkers like Houston Stewart Chamberlain and the eugenics movement provided a framework in which racial struggle seemed scientifically grounded. For Hitler, everything in history could be explained by the eternal struggle between races.
Jews, in his framework, were a uniquely dangerous race whose defining characteristic was a parasitic relationship with other peoples. Every German catastrophe, from 1918 to Versailles to economic chaos, was traceable to Jewish manipulation.
Munich, where Hitler moved in May 1913, suited him better than Vienna. When war broke out in August 1914, he volunteered for the Bavarian army despite being an Austrian citizen.
For a purposeless drifter, the war was a liberation. He served as a regimental messenger, a dangerous role, and was awarded the Iron Cross Second Class in 1914 and First Class in 1918, the latter recommended by a Jewish officer, a fact Hitler never acknowledged.
The trenches did not moderate his extremism. They confirmed and intensified it.
After the armistice, Germany was in crisis. The Kaiser had abdicated, revolution was spreading, and a Soviet-style council republic was briefly proclaimed in Munich before being crushed by right-wing paramilitary units in May 1919.
Hitler remained in the army as a political instructor. In September 1919, he attended a meeting of the tiny German Workers' Party and argued so forcefully that its founder, Anton Drexler, invited him to join.
Within months, Hitler had transformed this fringe group into the movement that would eventually seize control of Germany.
What Hitler believed in its most essential form was a racial cosmology. At the top was the Aryan race, which he identified with the Germanic peoples of Central Europe. At the bottom were Africans and Romani people.
But the most dangerous group in his thinking were the Jews, whom he regarded as a uniquely destructive counter-race. Marxism, democracy, the free press, and international finance were all, in his view, Jewish instruments.
This totalizing conspiracy theory led logically toward a conclusion implicit from an early stage: the problem of the Jews required their physical elimination.
If the struggle was truly existential, then war was not merely justified but obligatory. It was the most fundamental act of self-defense imaginable.
Beyond racial ideology, a second pillar made war necessary in Hitler's mind: Lebensraum, or living space. The concept held that a nation's power depended on the territory it controlled.
Germany, by this logic, was dangerously underpowered, squeezed into a small territory in central Europe while Britain, France, the United States, and Russia all had vast territories or empires.
The target of German expansion was not the colonial world but Eastern Europe and the Soviet Union. In Hitler's vision, the Ukrainian steppe, the mineral wealth of the Urals, and the oil fields of the Caucasus would give Germany the continental empire it needed.
Russia was perfectly suited for conquest because, in Hitler's view, it was run by Jews. The Bolshevik Revolution of 1917 was for him the supreme example of Jewish political subversion.
Germany would colonize the conquered east, expelling or exterminating the indigenous Slavic populations and settling German farmers in their place. This was not hidden. Hitler stated it clearly in Mein Kampf, published in 1925 and 1926.
The Great Depression gave Hitler his political opportunity. Germany's economy had never fully recovered from the hyperinflation of 1923, when workers were paid twice a day and life savings were wiped out.
When American loans were called in after the 1929 crash, the German economy collapsed. By 1932, over 6 million workers were unemployed, roughly one in three of the industrial workforce.
Into this crisis stepped Hitler, offering an explanation for the misery and a solution. His vote rose from 2.6 percent in 1928 to 18.3 percent in 1930 and 37.4 percent in July 1932, making the Nazis the largest party in parliament.
On January 30, 1933, President Paul von Hindenburg appointed Hitler Chancellor. Hindenburg despised him, calling him the Bohemian corporal, but conservative advisers convinced the old man that Hitler could be managed.
It was one of the most catastrophic miscalculations in democratic history. Within months, Hitler had dismantled the Weimar Republic.
The burning of the Reichstag on February 27, 1933, provided the emergency. The Reichstag Fire Decree suspended civil liberties and legalized mass arrests. Four weeks later, the Enabling Act gave Hitler the power to make laws without parliamentary approval.
Trade unions were dissolved. Political parties were banned. The federal structure was abolished. The judiciary was brought under party control. The press was muzzled under Joseph Goebbels.
The SS under Heinrich Himmler and the Gestapo silenced those who might have resisted. By 1934, after Hindenburg's death, Hitler merged the offices of chancellor and president and declared himself Führer.
The entire German military swore a personal oath of loyalty not to the state or constitution but to Adolf Hitler by name. This oath would constrain generals who later doubted his plans.
The removal of domestic checks on Hitler's power was a structural precondition for world war.
In March 1935, Hitler announced that Germany had been secretly rearming and would now openly reintroduce conscription, building toward 36 divisions. This flagrantly violated Versailles.
Britain, France, and Italy condemned the action at Stresa in April 1935 but took no practical steps. Weeks later, Britain concluded the Anglo-German Naval Agreement without consulting France or Italy, effectively approving German naval rearmament.
Hitler was jubilant. He had broken a fundamental provision of Versailles and the British had essentially thanked him for it.
By 1939, Germany had over 100 divisions, a modern Luftwaffe, and an advanced navy. But rearmament was financially unsustainable. Economics minister Hjalmar Schacht warned repeatedly that the program was outrunning the country's capacity.
Hitler's response was not to slow down but to accelerate the timeline for territorial expansion. New territories would provide raw materials and economic base for the next phase. The economic logic pointed toward war sooner rather than later.
The reoccupation of the Rhineland on March 7, 1936, was the most audacious gamble of Hitler's pre-war career. He sent just 19 battalions, about 3,000 soldiers, with orders to withdraw if French troops responded.
The German generals were terrified. Colonel Günther Blumentritt estimated the force could have resisted for about an hour. France did not move, and Britain had no appetite for confrontation.
The gamble succeeded completely. The lesson Hitler drew was that the Western democracies lacked the will to fight. Each successful bluff confirmed his contempt for Western leadership.
The Rhineland contained Germany's industrial heartland. A French occupation would have crippled rearmament and almost certainly ended Hitler's regime. Winston Churchill warned repeatedly that each year of inaction was a year of growing danger. He was ignored.
In August 1936, Hitler wrote the Four-Year Plan memorandum, distributed to only a handful of top officials. It declared that the Marxist Soviet state posed an existential threat and that Germany must be ready for war within four years.
The memorandum implied a specific timetable: Germany would be ready for the decisive war against the Soviet Union around 1940. Everything in the intervening years was preparation.
The Spanish Civil War, which erupted in July 1936, gave Hitler a valuable opportunity. He intervened on behalf of General Francisco Franco with the Condor Legion, testing German weapons and tactics under real combat conditions.
The destruction of Guernica by Condor Legion aircraft in April 1937 demonstrated what the Luftwaffe could do to civilian populations. Terror bombing became a central element of German doctrine.
On November 5, 1937, Hitler convened a secret conference recorded by Colonel Friedrich Hossbach. He told his military chiefs that Germany's problem was the need for Lebensraum, solvable only by force.
Germany must act no later than 1943 to 1945, Hitler said, because after that its military advantage would decline. Austria and Czechoslovakia must be liquidated first to eliminate the threat of a two-front war.
War Minister Werner von Blomberg and army chief Werner von Fritsch expressed serious reservations. Foreign Minister Konstantin von Neurath was equally alarmed.
Three months later, Hitler removed all three. Blomberg was discredited by revelations about his new wife. Fritsch was falsely accused of homosexuality. Neurath was replaced by the compliant Joachim von Ribbentrop.
Hitler took personal command of the armed forces, creating the OKW under the servile Wilhelm Keitel. The internal brake on his war plans had been removed.
Austria had been a target of German nationalist ambitions since 1918. For Hitler, an Austrian by birth, the Anschluss was both a personal and ideological imperative.
On February 12, 1938, Hitler summoned Chancellor Kurt Schuschnigg to Berchtesgaden and subjected him to hours of intimidation. Schuschnigg agreed to demands, then called a plebiscite on Austrian independence.
Hitler panicked and demanded the plebiscite be cancelled and Schuschnigg resign. On March 12, 1938, the German army marched into Austria.
Instead of confrontation, the soldiers were met with flowers and cheering crowds. The Anschluss was genuinely popular among a large proportion of Austrians. Hitler's triumphal drive into Vienna was greeted by enormous crowds.
Britain and France protested but took no action. Mussolini's Italy made no objection. Hitler's gamble had paid off again.
Czechoslovakia was next. Created in 1918, it was the most successful democracy in Central Europe, with a strong industrial economy and one of the best-equipped small armies in Europe.
It also had a powerful ring of mountain fortifications in the Sudetenland, home to over 3 million ethnic Germans. German planners estimated capturing them would cost tens of thousands of casualties.
Hitler's strategy was two-tracked. Publicly, he demanded self-determination for the Sudeten Germans. Privately, in directives beginning in May 1938 with Case Green, he ordered the military destruction of Czechoslovakia by October 1, 1938.
The purpose was not to liberate the Sudeten Germans, whom Hitler privately called a pretext. The purpose was to destroy the Czech state entirely and seize its industrial resources.
The Munich Agreement of September 29 to 30, 1938, saw Britain, France, Italy, and Germany agree to the transfer of the Sudetenland. Neville Chamberlain returned to London proclaiming peace for our time.
Within six months, Hitler had swallowed the rest of Czechoslovakia. On March 15, 1939, German troops marched into Prague and established the protectorate of Bohemia and Moravia.
This destroyed the entire framework of appeasement. The Sudeten Germans could have been accommodated under self-determination, but Czechs were not Germans. Hitler had simply taken a sovereign non-German country by force.
British and French public opinion was galvanized. Within days, Britain and France issued guarantees of military assistance to Poland, Romania, and Greece.
Hitler's response was not to pause but to accelerate. Within days of Chamberlain's guarantee to Poland on March 31, 1939, Hitler signed a secret directive ordering preparation for the invasion of Poland by September 1, 1939.
He dismissed Chamberlain as a little worm and was certain Britain and France would not fight for Poland. He was almost right.
On August 23, 1939, the Nazi-Soviet non-aggression pact was signed in Moscow by Ribbentrop and Vyacheslav Molotov. Its shock value was enormous.
A secret protocol divided Eastern Europe into spheres of influence. Finland, Estonia, Latvia, and eastern Poland went to the Soviet sphere; western Poland to Germany. A fourth partition of Poland was agreed before a single German soldier crossed the border.
For Hitler, the pact solved Germany's greatest strategic vulnerability: the risk of a two-front war. With the Soviet Union neutralized, Germany could deal with Poland and the Western powers with undivided attention.
Stalin believed the pact bought him time to complete Soviet rearmament. He was catastrophically wrong about Hitler's timetable.
Appeasement was not simply cowardice. British public opinion was profoundly pacifist after the First World War, which killed nearly a million British soldiers. The Oxford Union passed its famous 1933 resolution refusing to fight for king and country.
Many influential Britons genuinely sympathized with some German grievances. The Versailles treaty had been widely criticized even in 1919, and allowing Germany to absorb Austria and the Sudeten Germans seemed to many a belated rectification of injustice.
Britain was also not ready for war. The army in 1938 could have fielded only two divisions. The RAF had not yet received the Hurricanes and Spitfires that would win the Battle of Britain.
But appeasement failed for a fundamental reason. It assumed Hitler was a rational statesman with limited goals who would be satisfied once his legitimate grievances were addressed.
This was precisely wrong. Hitler was a revolutionary whose program required the conquest and racial reorganization of an entire continent. There was no final demand he would state and honor.
By the late 1930s, Hitler was also obsessed with his own mortality. Born in 1889, he was 50 when the war began and convinced he might not live long enough to complete his program.
At a meeting with commanders on August 22, 1939, Hitler reportedly said Germany's fate depended on him personally and there was no time to lose. If Germany waited for overwhelming superiority, the window might close.
There was also an economic driver: plunder. Rearmament had been financed by deficit spending and the seizure of Jewish property. By 1939, resources were running thin.
The logic of the Nazi economic system pointed toward permanent large-scale plunder of conquered territories. Each conquest brought new wealth, slave labor, and raw materials to finance the next.
Poland had been resurrected in 1918 after more than a century of partition. The Polish Corridor separated East Prussia from Germany, and the free city of Danzig was a source of endless friction.
In January 1934, Germany and Poland had signed a non-aggression pact. For five years, Polish foreign minister Józef Beck balanced between Germany and the Soviet Union.
By early 1939, Hitler had decided Poland's moment had come. In March, he demanded Danzig's return and an extraterritorial road and rail connection across the corridor.
The demands came days after Germany marched into Prague. Beck correctly understood them as the beginning of a program of coercion, not the opening of a negotiation. He refused.
When the British guarantee arrived on March 31, 1939, the Poles accepted it. For Hitler, this refusal was a personal affront as well as a strategic obstacle.
Hitler's military preparations for Poland were barely adequate. Germany had 58 divisions available, but most were under strength and many equipped with older weapons. The tank force relied largely on light Panzer I and II models.
German planners knew that if France attacked in the west while Germany was engaged in Poland, the Western Front could not hold for long. Germany gambled that France would not attack.
France did not attack. The French launched a token offensive in mid-September 1939, advancing a few kilometers into the Saar region before halting and withdrawing.
French military doctrine was fundamentally defensive, shaped by the trauma of the First World War. The Maginot Line was a physical expression of a mental attitude: France would defend, but not attack.
On September 1, 1939, at 4:45 in the morning, German forces crossed the Polish frontier and the battleship Schleswig-Holstein opened fire on the Polish fortress at Westerplatte in Danzig harbor.
The Polish campaign lasted just over five weeks. It demonstrated the revolutionary doctrine that became known as Blitzkrieg: armored columns penetrating deep behind Polish lines, encircling large formations, and the Luftwaffe destroying communications and airfields.
On September 17, the Soviet Red Army invaded from the east in accordance with the secret protocol. Poland's resistance was brave but overwhelmed from both directions.
For Hitler, September 1 was not the beginning of the war he had planned. It was a partial and unsatisfactory opening move in a much larger design. He had expected Britain and France to accept Poland's destruction as they had accepted Austria's and Czechoslovakia's.
Instead, he had a two-front war, precisely the situation German planners had always feared. Britain and France had declared war.
The German military establishment was not simply a captive instrument of Hitler's will. A significant number of senior officers harbored doubts, and in 1938 a group of generals had planned a coup if Hitler ordered the invasion of Czechoslovakia.
General Ludwig Beck, chief of the general staff, resigned in protest in August 1938, the only senior German general to do so in the pre-war period. But for every Beck who resigned, there were dozens who complied.
German heavy industry supported the Nazis financially and embraced rearmament contracts. Companies like Krupp, IG Farben, Thyssen, and Flick grew fat on Wehrmacht contracts. Many of their leaders were genuine ideological allies.
The German public in 1939 was not overwhelmingly enthusiastic about war. The dominant mood was between resigned acceptance and anxious apprehension. The memory of the First World War was only 20 years old.
What silenced public doubts was a combination of factors: economic recovery and full employment, Goebbels's sophisticated propaganda machine, and the climate of fear created by the Gestapo.
The Night of Broken Glass on November 9 to 10, 1938, offered a window into the trajectory of Hitler's Jewish policy. Organized pogroms destroyed thousands of Jewish businesses and synagogues and resulted in the arrest of approximately 30,000 Jewish men.
The scale of violence shocked many Germans. But the international outrage was met with defiant indifference. Hitler viewed the pogrom as an opportunity to accelerate the dispossession of German Jews.
Could the war have been prevented? The answer depends on when the question is asked. In 1933, firm Anglo-French commitment backed by credible force might have deterred the Nazi program.
In 1936, French military action in response to the Rhineland reoccupation would almost certainly have ended Hitler's regime. Even in 1938, a firm declaration over Czechoslovakia might have given the German generals planning a coup the support they needed.
By 1939, after Munich, after the Nazi-Soviet pact, the war had become extremely difficult to prevent.
The failure of collective security was as much a reason for the war as any of Hitler's convictions. The League of Nations had been weakened from the start by the American refusal to join and by the gap between its covenant and its members' willingness to honor it.
When Japan invaded Manchuria in 1931 and Italy invaded Abyssinia in 1935, the League's response was embarrassingly ineffective. Hitler paid attention. He understood the international order would not effectively resist a determined great power.
The Weimar Republic's structural weaknesses were another deep-rooted reason. Born under defeat, revolution, and hyperinflation, it never enjoyed the legitimacy that comes from national success.
Proportional representation fragmented parliament into dozens of parties. Article 48 allowed rule by presidential decree. Once the Nazi and Communist parties together held a blocking majority, no stable government was possible.
The German Communist Party, following Moscow's line, refused to cooperate with Social Democrats against the Nazi threat, describing them as social fascists. This sectarianism meant the German left could not mount a united front.
The conservative right was determined to use the Nazis to destroy the left, not understanding that Hitler would eventually consume them too. Hitler did not seize power so much as he was handed it by men who thought they could control him.
History is not inevitable. It is the product of choices. If Hindenburg had refused to appoint Hitler in January 1933, the Nazi moment might have passed. If the generals had carried out their coup in 1938, the regime might have fallen.
No individual made more consequential choices than Adolf Hitler himself. What made him uniquely dangerous was the combination of extraordinary political talent with a worldview so radical it could not be satisfied by any conventional settlement.
He was a superb political intuitive with an uncanny ability to sense and exploit the weaknesses of opponents. He understood that the rules of the liberal international order could be broken by anyone with the will to break them.
Hitler's war, when it came, was both the logical conclusion of everything he had worked toward since the early 1920s and a desperate gamble he was not fully ready to make.
The deeper reasons were a complex web of ideology, personality, history, economics, and strategic calculation. Versailles created the grievances. The stab-in-the-back myth turned them into paranoid conspiracy thinking.
The Great Depression destroyed the stability that might have contained German nationalism. Hitler's racial cosmology and Lebensraum program transformed it from a revisionist force into a revolutionary one.
The weakness of Weimar allowed him to come to power. German industry and the officer corps provided the tools. Appeasement gave him time to build and use them. The Nazi-Soviet pact removed the eastern threat.
Poland's refusal to submit and the British and French guarantees forced the issue to a military conclusion in September 1939. None of these factors alone would have been sufficient. Each was necessary.
But the most fundamental reason was the existence of Adolf Hitler himself. A man who used the tools of democracy to destroy democracy, who exploited the legitimate grievances of a humiliated nation, and who never deviated from the conviction that Germany must conquer or perish in the attempt.
The Second World War was in the most essential sense Hitler's war. It began because he willed it to begin, at a time and in a manner determined by his specific ideological agenda.
Fear also played a role. Hitler was afraid of Bolshevism, which he saw as a Jewish-directed extermination campaign against the Aryan race. He was afraid Germany's window of military advantage would close.
He was afraid he would not live long enough to accomplish what he believed was his historical destiny. Above all, he was afraid of a repetition of 1918, of another defeat and another stab in the back.
The Italian alliance emboldened him but had limitations. Italy's military was weaker, and Mussolini was an independent operator. When Hitler invaded Poland, Mussolini declared Italy non-belligerent, citing lack of preparedness.
Propaganda prepared Germany for war. Goebbels's ministry controlled every medium. By 1939, Germany had the highest radio ownership rate in Europe, partly through subsidized cheap receivers that could not pick up foreign broadcasts.
The particular genius of Nazi propaganda was that it worked through atmosphere, spectacle, and emotional manipulation rather than explicit instruction. The Nuremberg rallies were instruments of psychological transformation.
The suppression of internal opposition was another key reason Hitler could start the war. Millions of Germans had never voted Nazi. Hundreds of thousands belonged to trade unions, churches, and civic organizations.
But the physical terror of the SS and Gestapo was genuinely frightening. The legal system was corrupted. The Communist Party was destroyed in 1933. The Social Democrats were banned. The trade unions were dissolved.
By the time the regime's criminal character was fully apparent, the apparatus of repression was too powerful to be challenged from within without outside military defeat.
In April 1939, Hitler signed the directive for Case White, the plan for the invasion of Poland, with a provisional date of September 1. He communicated his fundamental assumption: Britain and France would not fight.
Throughout July and August 1939, Hitler received messages suggesting Britain was looking for a way to avoid war. He interpreted these as evidence that Britain was irresolute. He was partly right and partly wrong.
Chamberlain desperately wanted to avoid war, but by August 1939 the British government had concluded that surrender to Hitler's demands would be worse than war. When the German army crossed the Polish border, Chamberlain had no choice but to honor the guarantee.
The war that began on that gray September morning was larger, longer, and more devastating than even the most pessimistic observers had imagined. Poland fell in five weeks, but Britain and France did not make peace.
The Phony War gave Hitler time to reorganize. In April 1940, Germany invaded Denmark and Norway. On May 10, 1940, the great western offensive began.
Within six weeks, France had fallen. The British Expeditionary Force was evacuated at Dunkirk, leaving virtually all its heavy equipment behind. The man who had gambled on Western weakness had been proved right, at least in the short term.
But the very success of the Western campaign planted the seeds of Germany's ultimate defeat. It encouraged in Hitler a dangerous overconfidence that led to his greatest blunder: the invasion of the Soviet Union on June 22, 1941.
Operation Barbarossa was the war Hitler had always wanted to fight, the war for Lebensraum and against Jewish Bolshevism. But it was also the war that would destroy him.
The Soviet Union did not collapse as he had predicted. The Red Army did not crumble. At Stalingrad in the winter of 1942 to 1943, the Sixth Army was encircled and destroyed. The strategic initiative passed to the Soviets and never returned.
The United States entered the war in December 1941 after the Japanese attack on Pearl Harbor, and Hitler declared war on America three days later. Germany was under no treaty obligation to do so.
Whatever his reasoning, the declaration brought the world's largest industrial economy fully into the conflict against Germany and made German defeat only a matter of time and cost.
The Holocaust, the systematic murder of six million European Jews and millions of others, was the fullest expression of the ideological program that had driven Hitler to start the war.
The decision to move from persecution to systematic mass murder was taken in stages between 1941 and 1942. The Einsatzgruppen murdered over a million Jews in mass shootings, including 33,000 at Babi Yar in two days.
The Wannsee Conference of January 20, 1942, coordinated the bureaucratic apparatus for the Final Solution. The extermination camps at Auschwitz-Birkenau, Treblinka, Sobibor, Belzec, Chelmno, and Majdanek were the logical conclusion of the racial ideology at the core of Hitler's worldview.
Without the war, without the conquest of Poland and the Soviet Union and their large Jewish populations, the Holocaust as it occurred could not have happened. The connection is structural, ideological, and direct.
The legacy of the war is still with us. The 70 million dead, the tens of millions displaced, and the cities reduced to rubble required decades to rebuild.
The political map of Europe was redrawn. Germany was divided, Eastern Europe fell under Soviet domination, and Western Europe bound together in an unprecedented experiment in integration, partly to make another European war impossible.
The United Nations embodied the lesson that collective security required genuine commitment and real military capacity. The Nuremberg trials established that crimes against humanity and aggressive war were prosecutable offenses under international law.
The question of how an advanced, educated, and culturally sophisticated society came to embrace Nazism remains one of the most pressing moral questions of the modern era.
The answer involves the specific historical conjuncture: the traumatic defeat of 1918, the humiliations of Versailles, the destabilizing effects of hyperinflation and depression, the structural weaknesses of Weimar, and above all, the specific genius and specific madness of Adolf Hitler himself.
Why did Hitler have to start World War II? The answer in all its complexity is that he started it because he had always intended to.
His entire political career from 1919 to 1939 was the systematic preparation for this war. His ideological convictions, his psychology, his political genius, the weaknesses of German democracy, the grievances of the German people, the failures of appeasement, and the brutal logic of his rearmament economy all converged in September 1939.
He was wrong about its outcome. He was not wrong that he was the man who made it happen.
History does not repeat itself precisely, but it rhymes. The combination of genuine social grievances, economic desperation, ideological extremism, contempt for democratic institutions, and the failure of international institutions to enforce collective norms against aggression are recurring human tendencies.
The men and women of the 1930s who failed to stop Hitler failed mostly not because they were evil but because they were afraid or mistaken or unable to believe that a civilized modern nation could be led by someone who genuinely meant what he said.
The most important lesson of the entire terrible story is to believe people when they tell you what they intend to do. Hitler told the world exactly what he intended. The world chose not to believe him until it was too late.