Army Historian Answers World War II Questions

PeePeePooPooMan42 asks,

How did the allies in World War II decipher German enigma?

As a former military intelligence officer myself, the story

of breaking the Enigma codes is fascinating to me.

I'm Peter Knight from the US Army

Center of Military History.

Let's answer your questions from the internet.

This is World War II Support.

[upbeat music]

AceofSpades629 asks, What is the best statistic

that puts the scale of World War II into perspective?

One statistic

that really stands out is the death toll,

upwards of 85 million people,

including military and civilians perish.

There were 100 million combatants from 50 nations.

In terms of gross domestic product spending,

the United States spent between 35

and 40% annually, Germany 50%.

Here is a question from Quora.

What is the timeline of World War Two?

Most historians

and scholars agree, the proximate start

of the Second World War is Hitler's invasion

of Poland on September 1st, 1939,

because at that point,

Hitler's invasion causes Great Britain

and France to declare war on Germany

because they have guaranteed the security of Poland.

Our next point will come in 1941

when the Soviet Union is invaded by Hitler.

Russia had initially signed a non-aggression pact

with Hitler, and they agreed to divide Poland

between them when Hitler invaded in September,

however, Hitler turns the tables on Joseph Stalin

and invades the Soviet Union in the summer of 1941.

This brings us to our third turning point,

the Battle of the Atlantic in 1943.

This is a battle for control of the Atlantic Sea lanes

that enable the United States

to send war material across the Atlantic

to the aid of Russia and Britain.

Unless they can secure those sea lanes,

that equipment will be taken out

and the German U-boats run roughshod,

sinking millions of tons of Allied shipping.

Our next point would be the D-Day landings

on June the sixth, 1944, the allies established a beachhead

and a foothold on the continent of Europe

and open up a crucial second front

against Hitler's Nazi forces.

Our next major point are the two atomic bombings

on Hiroshima and Nagasaki on August the sixth

and the ninth 1945, Emperor Hirohito

knows it's only a matter of time

and he gives a radio address.

This is the first time that many

of his subjects in Japan have ever heard his voice,

and he asks them to endure the unendurable

and submit to the unconditional surrender

to the allied powers, which brings us to our final point.

September 2nd, 1945, the Japanese sign the instrument

of surrender aboard the USS Missouri in Tokyo Bay

and World War II is brought to an end.

HHT_Lucas asks,

Y'all ever think about how the Nazis were on meth

like all the time?

Nazi soldiers did indeed

get methamphetamines distributed to them.

The idea was that these very powerful drugs

would allow them to stay awake for longer periods of time,

would enhance their mental alertness,

their aggressiveness, essentially enable them

to succeed and win in combat.

But there were some significant side effects,

extreme exhaustion and hallucinations.

That being said, it wasn't just the troops

that were getting drugs.

Hitler received all kinds of opioid injections, oxycodone,

cocaine that were used to help him cope

and get through his day.

On the allied side, GIs and and other allied troops

got what were called Go pills,

Benzedrine, which was an amphetamine, not a methamphetamine.

So these are less powerful

and less potent than the pills the Germans were taking,

and most of the time, Benzedrine was used by allied pilots

that were on these very long bombing run missions,

just to stay awake.

Nobodygrotesque asks,

What are some World War II movies

that are the most historically accurate

that one can learn from?

the Steven Spielberg film Saving Private Ryan

its opening sequence

of the troop landings on Omaha Beach on D-Day

are some of the most realistic depictions I've ever seen,

and they're based largely on soldier accounts.

There's a moment where you'll see soldiers disembarking

from the landing craft and they'll immediately

be submerged in the water.

That's very true to life

because as the landing craft approached the beaches,

some of the parts of the beach

had received some early naval gunfire

and there were craters

and they're stepping off into water

that is over their heads.

So some of these soldiers

who are immediately immersed in the water

and sinking like a stone, they're panicking

and they're getting shot at it the same time,

and some of these unfortunate soldiers

will drown in the process.

Another movie is The Longest Day based on the book

by Cornelius Ryan that shows a lot of the D-Day activities.

For example, the use of dummy paratroopers,

these little straw men that they dressed up

to look like soldiers

and they'd throw them out of the aircraft

to confuse the German forces

as to where the airborne divisions were going to land.

The German term for the dummy was gummipoopen,

and you hear them talking about this over the radio

and they're just ranting about it.

[speaking in foreign language]

It's somewhat humorous in that context.

Kyle Lindsey has a question Ever heard

of the Ghost Army in World War II?

It's one of those wild true tales

that sounds like a Hollywood script, but actually happened.

The name of the unit

is the 23rd Headquarters Special Troops Unit.

This unit's mission is to create the illusion

of military forces in different places

through the use of inflatable tanks,

inflatable troop carrying ships,

fake weaponry, fake radio transmission traffic,

all for the purpose of deceiving

the Axis powers into thinking

that certain troop formations might be larger

than they actually were,

or in the case of the preparation

for Operation Overlord, D-Day,

creating an entire fictional first US army group

allegedly led by General George S. Patton

that would make a landing at the Pas de Calais

as opposed to Normandy

and selling the Germans on that fake plan.

AnniElocin writes, I still don't understand.

Why would Japan bomb Pearl Harbor?

One of the biggest reasons why Japan

decides that they have to attack the US Pacific fleet

is because of an oil embargo

President Franklin Roosevelt imposed upon Japan.

Pearl Harbor is located on the island of Oahu.

Admiral Isoroku Yamamoto,

chief of the Imperial Japanese Navy

believes that they must strike

and cripple the US Pacific fleet

in order to allow Japan the freedom

to embark on their military campaigns

to conquer the Dutch East Indies

and British Malaya over here

that contain the natural resources, oil

and rubber that the Japanese absolutely need

to sustain their war machine and their industrial economy.

If we look at where Japan is, the Philippine Islands

is between the Japanese home islands

and those desired targets.

The United States controls the Philippine Islands

and they will be attacked within nine hours

after the attack on Pearl Harbor.

The Japanese will attack Pearl Harbor

on Sunday morning, December 7th, 1941.

They will succeed in crippling several of the battleships,

especially the USS Arizona

that will carry over 2000 soldiers to their death,

and it does do a lot to set back the US Pacific fleet,

but it does not succeed in destroying it.

Japan missed our oil and fuel refineries

and our big dry dock facilities that will enable us

to continue to fuel and supply our fleet and repair it

and recover from the loss.

@MatchlessMine asks,

When did Hitler declare war on the US?

Adolf Hitler declares war on the United States

on December 11th, 1941, a mere four days

after the Japanese attack Pearl Harbor.

Sipwell asks How effective were German U-boats

in World War II?

From the start in 1939, easily through most of 1942,

German U-boats successfully sank over six million tons

of allied shipping.

You're sinking allied shipping

faster than the allies can build the ships.

Some of those sinkings occur within sight

of the US coastline.

The biggest single factor

that turns the tables on the German U-boats

is the cracking of the German enigma codes.

The cracking of the enigma codes allows the allies

better success in locating the U-boats and destroying them.

This is huge because with the German U-boat threat negated,

this enables the allied forces to move enough men

and material, planes, vehicles, weapons over to England

to be able to stage for the invasion of Western Europe.

PeePeePooPooMan42 asks,

How did the allies in World War II decipher German enigma

if there were millions of possibilities for letters

and it was being changed every day?

I absolutely love this question.

As a former military intelligence officer myself,

the story of breaking the enigma codes

is fascinating to me.

The allies are able to crack the German enigma

due to a number of different factors.

Polish cryptanalysts

and mathematicians were able

to reconstruct the German enigma machine

and smuggle a version of it out of Poland

just as the Germans were invading

in September, 1939, that copy of Enigma

was given to the British.

The British then take it

and put it in the hands of their cryptanalysts

working out of Bletchley Park

and those cryptanalysts partner

with American mathematicians and cryptanalysts

and one in particular by the name of Alan Turing.

He is able to invent an electro mechanical machine

that is able to compute the different combinations

that the enigma machine can generate

and then they're able to crack the enigma codes

because of the human frailties of the system.

Those who would be creating enigma traffic

would use certain phrases the same way each day

and looking for those same phrases or messages

or plain text, which we refer to as cribs,

helped the code breakers be able to determine

what the enigma machine settings would be.

Most experts will estimate the cracking

of enigma alone shorten the war

anywhere between two and four years.

Here's a question from World War II Subreddit.

How far back does the chain of events go

to lead to World War II?

World War II has its roots in the First World War

and the Treaty of Versailles,

Germany is forced to pay crippling reparations

to demilitarize and accept full responsibility

for the First World War.

This, combined with the Great Depression

absolutely cripples the German economy

and the German people are looking

for a hope, a way out of this.

Adolf Hitler provides that

by promising to remilitarize Germany,

to revive the German economy

and its war machine for the purposes

of territorial expansion.

In the meantime,

Japan embarks upon imperial expansion,

invading China in 1931.

These are the chain of events that set things in motion.

A question from the Ask Historian Subreddit is,

Were there any nations totally unaffected by World War II?

The short answer to that question is no.

Although there are 14 nations

that maintained neutrality status

throughout the entirety of the Second World War.

Among those 14 were nations like Sweden, Switzerland,

Yemen, Saudi Arabia, Turkey, Ireland,

small little states like Lichtenstein and the Vatican City,

and they would help either side as it suited their purposes.

This map, although it's in Russian,

certainly shows you the battle lines

and movements of large troop formations across the globe

over the course of the Second World War.

And as you can see, the war leaves basically

no part of the planet unscathed.

Here you can see a lot of the action in Europe.

You look in the Pacific,

it's a much more spread out, wide area,

different island chains,

but then India of course is part of the British empire,

and so Britain is going to fight to protect that

and the China Burma India area is referred to

as a China Burma India theater

where the American Commander Vinegar Joe Stilwell

works to advance allied interests

and defeat Japanese forces in this area.

So as you can see,

between the European Theater of Operations

and the Pacific Theater of Operations,

this is truly a global conflict.

RippinDankBonks wants to know What was the point

of the invasion of Normandy from a tactical standpoint?

The invasion of Normandy

from a tactical standpoint probably doesn't make

a lot of sense to the average viewer

when you have to fight up over the beach

against elevated German positions in concrete pill boxes,

it seems like an impossible task,

but you have to remember,

you can't just airdrop armored divisions

from planes onto the ground in Europe,

there are German armored forces

already on the continent.

They have to create a beachhead.

The Normandy beachhead is the ideal place for the allies

to strike because it is the weakest point

of the Atlantic wall defenses

and it has the best beach front area

to make their amphibious assault

onto the continent of Europe.

This picture is taken just after D-Day.

Now they're gonna begin