Order of WWII events:

  1. 1937: Japan attacks China
  2. 1939: Germany & Russia invade Poland, France and Britain declare war on Germany
  3. 1940: Italy allies with Germany
  4. 1941: Germany invades Greece, Yugoslavia + Romania, Russia. Declares war on Russia.
  5. 1941: Japan attacks American/British/Dutch/Portugese territories in Southeast Asia
  6. 1941: Grand Alliance Allies between Britain, USA, USSR, China
  7. 1945: Russia declares war on Japan.

Nature of WWII

Total war between major industrial nations, second and last of kind (in part because nukes).

61 countries w/1.7e9 citizens (3/4 world population) involved. 1.1e8 mobilized. ~2.6e7 USSR, 1.7e7 DE, 1.6e7 USA. Largest # of participants on duty at any one time: 1.25e7 USSR, 1.2245e7 USA, 1.0938e7 DE, 8.72e6 British Empire & Commonwealth, 7.193e6 JP, 5e6 China.


WWII contains multiple linked conflicts. In Europe, FR & GB vs DE because Versailles. (DE wanted Poland because former territory, GB had guaranteed Poland independence & FR supported it.) Versailles not only factor.

War started w/JP, DE, IT trying to get territories they saw as theirs for ideological & economic regions.

LoN weak, initial resistance weak, resistance grew & Allies halted further expansion by 1943 before counter-attacking.

Allies had more resources, were as determined as Axis, industrial stuff & tech important.

Civilian casualty levels unprecedented. DE wanted racial destruction, Allies wanted unconditional surrender, less distinction made between military and civilian targets (see Hiroshima).

War affected political & socioeconomic life. Zedong & Stalin extended communism, creating cold war. EU empires ended, USA & USSR superpowers.

After WWII

Allies got lasting/decisive victory (regime change in DE and IT). Costs/risks of repeat too high, no major power’s done this much total war since. In Cold War, USSR and West got lots of unusable power. Lots of proxy warfare (wars among peoples).

What were long-term causes?

Impact of Versailles

Versailles not as bad for DE as FR wanted. Still major cause of WWII. DE hadn’t been occupied in 1918, had gained land in Russia, had been successful just prior to armistice, Western forces not destroyed, winning just seemed unlikely. Armistice not surrender, but FR thought otherwise. Subsequently, DE had many internal problems & food shortages and was forced to accept a settlement more appropriate for a surrender. (Couldn’t negotiate, promised 14 points not honored, no acknowledgement of Δgovernment, military restrictions & territory&colony loss humiliating and bad economically, reparations painful.) Germany left in crisis, encircled by FR & USSR. Treaty seemed unacceptable in long term, changeable only by negotiations (not that feasible) or force.

Marshal Foch (FR): It is not a peace. It is an armistice for twenty years.

DE felt vulnerable: Smaller army than neighbors, near aspiring-communism-spreader USSR, couldn’t assist German speakers in other countries, reliant on other economies. Ruhr Crisis (1923, FR & Belgium occupying Ruhr) humiliating and made GB sympathetic. GB wanted to relax Versailles treaty, disliked FR hard line of weak Germany. (FR’s hard line maybe would have prevented WWII?) At Locarno, GB & FR seemed willing-ish to let DE revise eastern borders.

League of Nations

LoN couldn’t control aggression of larger powers. In 1923, couldn’t handle Italian bombardment of Corfu on own. USA wouldn’t join, USSR only there 1934-1939. Dependent on GB and FR. GB & FR unprepared to back anti-Italian action due to Corfu or Abyssinia. Aggressors like JP (1933) and IT (1935) just left when criticized. LoN had no army or committed support, could not halt war. Other countries saw confronting aggression as LoN’s job.

What were short-term causes?

Post-1929 economic & political factors

In late 1920s Europe optimistic. FR & DE on good terms, GB promoting cooperation & trading with DE, US lent DE money. DE economy booming. 1929 economic crash & rise of nationalist regime in DE ended this. (New regime wanted to make DE world power by ending Versailles.)

DE farmers didn’t share 1920s boom, suffered from price drop on food. 1929 crash made US retract loans. DE banks collapsed, hurting businesses. Unemployment rose. Urban workers, small businesses, farmers all victims of unstable global economy. Extremists flourished. Communists offered social revolution & controlled economy. Nazis (note: National socialists) stood for national revival, punishing those responsible for current mess, new protective Germany. Hitler blamed Versailles (esp. reparations) for economic problems, as well as wealthy Jews. Called Jews, defeatists, socialists November Criminals and blamed them for accepting armistice. Nazis said DE needed strong army to fight enemies and Lebensraum for expansion (at expense of Slavs, who were seen as inferior and whose control of regions with German minorities was seen as insulting). Nazis had charismatic leader and good paramilitary forces.

Hitler’s political vision a cause of war

Hitler born 1889 in Austria. Moved to Munich 1913, served in German army. Joined right-wing nationalist German Workers’ Party (later became Nazi Party) and drafted ideological solutions to DE problems. Tried Beer Hall Putsch 1923, failed, wrote Mein Kampf while jailed for 9 months. Became chancellor 1933, set up dictatorship, had policies contribute to 1939 war.

Revising Versailles became part of vision for future in which Germany was a great power. Rearmament a goal. No Germans under foreign rule a goal. Hitler/Nazis wanted racial state to eradicate Communism and claimed Judeo-Bolshevik conspiracy had taken over Russia and threatened DE. Accomplishing these goals would allegedly lead to large regions for Germans to settle and a state lasting 1e3 years.

Doing even part of this vision would cause war. GB & FR wouldn’t accept dominant DE in central Europe. French security would be threatened. DE annexing German-populated lands and assaulting communist Russia would challenge all of Europe as established in 1919.

In 1933, FR & GB hoped Hitler would be more normal and that they could renegotiate Versailles while preventing or shielding themselves in the event of war.

Appeasement as a cause of war

New facts:

Few attempts made to defend Versailles, prevent DE rearmament, make anti-DE-expansion alliances.

Churchill said at the time that appeasement made war more likely. Some say Chamberlain had few options besides buying rearming time b/c public opinion, bad economy, flaky allies, not enough military.

Anti-appeasement case

If GB & FR had made DE leave DMZ in 1936, Hitler would have been humiliatingly defeated, public & military support would have decreased. After Rhineland, rearmament a pain to stop, and Anschluss made Czechoslovakia hard to defend.

After GB & FR began to give in, Hitler had no reason to expect sudden opposition. Appeasement showed they couldn’t keep commitments. When crowds cheered Chamberlain and Daladier after Munich, Hitler decided he could expand faster due to GB & FR unreadiness. Lack of commitment on other issues made Polish Guarantee seem equally empty.

Alternate view

Appeasement didn’t write Versailles or trash economy (bad economy = more isolationism). USSR & USA not part of European politics and their intervention seemed unlikely. 1-party dictators new & confusing.

Nazi Ideology

DE taking Poland 1st major WWII thing in Europe. Intended to regain lost territory but also ideological: Enslaved Poles and persecuted & killed Jews because alleged racial inferiority. WWII transitioned from being about Europe balance of power & Versailles to being about Nazi ideology. War also had Nazism vs Communism.

Hitler’s 1941 USSR invasion

Motivated by:

DE was overconfident and didn’t prepare enough. Lots of Soviets surrendered at first. After armies went through, Einsatzgruppen went through to kill Jews, Roma, Communist officials, and random people.

Ideology in GB & USA

Churchill & FDR wrote Atlantic Charter 1941-08-14. Affirmed self-determination & free trade, which constituted anti-fascism.

The balance of power

GB & USA could have done nothing. Populations isolationist, politicians needed public support. No real desire to expand territory. However, if DE controlled Northern Europe’s coastline, GB security & trade would be threatened. USA security not at risk, but DE controlling Europe would lead to controlled markets there, and JP controlling Asia would also threaten US trade.

Sans USA support, in 1940 GB couldn’t stay in WWII.

America and WWII

Isolationism popular because WWI unpopular. 100% isolationism impossible. Post-1933, FDR needed to pacify pro-recovery public but also deal with US interests abroad. FDR helped war expand outside Europe.

FDR pro-democracy, but FR & GB imperial powers. GB near Nazis in badness for some colonies. GB & empire had tariffs on trade w/US. FDR wasn’t persuaded to intervene in 1940, kept giving GB credit, offered old destroyers for West Indian bases. GB hoped USA would aid them.

Germany declares war on USA

JP attacked Pearl Harbor 1941-12-07. DE declared war on USA 4 days later. This linked 2 conflicts. JP-DE relations distant, DE hadn’t told JP it was going to invade USSR. USA upset, but this could have made USA focus on JP and ignore DE.

DE war against USA linked the following: GB vs DE (Versailles linked to Nazism vs Communism), GB & USA linked in Far East. This turned lots of wars into 1 World War.

DE declaring war seen as: hateful madness, thanking Japan, ending undeclared war in Atlantic between USA ships and DE U-boats. DE declaring war would allow it to attack Allies-aiding USA shipping. Grand Alliance (GB, USA, USSR, China) formed to fight DE, IT, JP.

A world war – the conflict in Asia

Japan rose as regional power in 1800s. Modernized rapidly, built military, didn’t have enough raw materials to be great power it wanted to be. Had lots of national pride and so on.

1911 revolution ending Manchu Qing dynasty threw China into chaos, JP demands threatened Chinese sovereignty. (1915-01-18 JP demanded China give JP Manchuria & Shandong, and accept JP advisors in gov’t. JP got former DE Shandong areas from Versailles but was forced to give them to China in 1921-22.) JP also offended by lack of racial equality in LoN principles. IT, RU, JP all saw self as losing in Paris treaties and made friendship treaties.

JP parliamentary in name only. Ruled by Emperor + family & military chiefs. Officer classes powerful and had little oversight in border regions.

JP saw survival as depending on access to raw materials, fuel, markets, especially after economic crash. Self-sufficient empire sought.

JP also felt foreign influence was corrupting it.


Manchuria had lots of raw materials: Coal, iron ore, bauxite, soya. Nationalist control of Manchuria weak, JP negotiated w/local warlords. In economic depression’s 1939-09 peak, JP soldiers staged explosions on JP South Manchuria Railway for invasion pretext, Tokyo forced to support them.

JP ignored protests, left LoN, established Manchukuo as puppet state, waged war in nearby areas. JP control of China undesirable to great powers because trade interference & colony interference. Sans USA leadership, little action possible.

JP began invading China @ scale in 1937. JP army competent. Chinese Nationalist gov’t distracted by communists, nationalists & communists not unified.

JP committed atrocities (see: Nanjing), felt China would solve trade issues. JP found war difficult, costly, unpopular w/Europe & USA. JP occupied French Indochina in 1940 to cut off Jiang’s supplies, GB felt this put Singapore, Malaya, Borneo, HK at risk. Dutch East Indies, Portugese Timor & Macao, US Phillipines also seen as at risk. (Territories had lots of oil, rubber, rice.)

Japan also could potentially invade Russia w/DE, but Anti-Comintern Pact didn’t force them to. US froze JP assets, supported GB through trade, had virtual anti-JP embargo on oil & ore.

Japanese position by 1941

JP forces busy, JP econ not competitive w/USA, in no position for lengthy war. USA econ pressure humiliating and prevented conquering China. USSR busy w/DE, FR defeated, GB distracted in Mediterranean & Atlantic. JP wanted a rapid strike for strong defense perimeter. Felt that Greater East Asia Co-Prosperity Zone could supply its forces. Also had nationalist status-seeking reasons.

Linked conflicts, similar causes

JP & DE overconfident, underestimated economic & military strength of enemies. Both failed in first objectives (Moscow & Leningrad, Pearl Harbor didn’t destroy aircraft carriers). Began wars not finishable by negotiations.

General causes in DE, IT, JP

Militarism: DE had major militarism since 1600s, was unified through war. Felt military could achieve political aims. IT had Piedmontese-dominated army w/tradition, built up forces in Ethiopia & Spanish Civil War. DE & IT had paramilitary fascist groups. JP had traditional feudal armies and powerful samurai, whose power was transferred to emperor & state after 1868. High-prestige military.

Nationalism & ideology: DE had much nationalism after 1871, valued German culture, wanted to control all German-speaking regions. IT nationalism slow and based on Roman Empire, Mussolini reversed 1896 Ethiopian defeat. JP had expansion as emperor-worship and also racism.

Economic pressure: Military spending needed for Nazi DE prosperity. This created inflation & shortages, leading to need for taking material goods through warfare. Mussolini mostly wanted economic gains for prestige. JP short on raw materials.

Political factors: Hitler wanted 1000-year empire of Aryans controlling Europe. War portrayed as anti-Versailles and starting 1941 as anti-Communist. Mussolini got prestige for successes but also peacekeeping. Easy victories lured him. JP wanted to free Asia from colonialism … to Japanese protection. Conquered territories exploited.