The document outlines several reasons for tensions between the Western allies (US and UK) and the Soviet Union during World War 2 that contributed to the start of the Cold War. These included disagreements over the timing of opening a second front in Western Europe, Soviet war crimes like the Katyn massacre that were ignored, the Soviets refusing to help the Warsaw uprising against the Nazis, and conflicting post-war visions over Poland's sovereignty at Yalta and Potsdam. However, the allies also achieved cooperation during the war and reached agreements, undermining the narrative that these events directly caused the Cold War.

1. The Cold War
1945-1989
Tensions in the
wartime alliance
Reasons that the Cold War started

2. Reasons the Cold War started
When World War Two
began in 1939, neither
the USA or USSR were
involved.
Both joined in 1941:
• the USSR after
Germany invaded in
June
• the USA after being
attacked by Japan in
December.

3. Reasons the Cold War started
Throughout their time
in the war, the USA
and USSR were
officially allies.
This meant they fought
on the same side.
However this hid
various disagreements
that they had during
the conflict.

4. Reasons the Cold War started
One major argument
between the two sides
was about the timing
of an invasion of
western Europe to open
a Second Front.
Most fighting in the
war was done on the
Eastern Front, between
the Soviet Union and
German forces.

5. Reasons the Cold War started
The Eastern Front saw
many bloody battles,
including the Battle
of Stalingrad (where
more than 1.1 million
Soviet soldiers were
killed or injured).
Up to 30 million
Soviets are believed
to have died during
the entire war.

6. Reasons the Cold War started
The Soviets
repeatedly demanded
that the USA and UK
launch an invasion of
France and Belgium to
divide German forces.
This would relieve
pressure on the USSR.
However this did not
happen until D-Day in
June 1944.

7. Reasons the Cold War started
The failure of the USA
and UK to launch an
attack led to anger
from Soviet leader
Joseph Stalin.
He believed the USA
wanted Germany and the
Soviet Union to
destroy each other.
These tensions led to
the Cold War.

8. Reasons the Cold War started
However Britain and
the USA did not attack
the USSR – instead
they did eventually
launch an attack on
the Western Front.
This undermines the
idea that Western
Front arguments
directly caused the
Cold War.

9. Reasons the Cold War started
In 1943, a series of
mass graves were
discovered in Poland.
This became known as
the Katyn Massacre.
In 1940, the USSR –
who invaded Poland
shortly after Germany
- had executed 22,000
Poles (including
military leaders).

10. Reasons the Cold War started
It was Germany who
discovered evidence of
the Soviets’ massacre.
They publicised this,
hoping to divide the
USA, UK and USSR.
However the USA and UK
took no action, even
ignoring evidence
which proved what the
Soviets had done.

11. Reasons the Cold War started
The USSR’s brutal
killings proved they
could not be trusted.
The USA did not take
action during WW2
because Soviet help
was needed to beat
Germany. When the war
ended this was no
longer the case,
dividing the two.

12. Reasons the Cold War started
The USA and UK were
aware of the Soviets’
actions at Katyn yet
still remained allies.
Even after the war
ended, neither country
did much to try to
punish those in the
Soviet army that
carried out the
killings.

13. Reasons the Cold War started
In August 1944 the
USSR had moved through
much of Poland. As
their army approached
Warsaw, an uprising
started in the city
against the Nazis.
About 16,000 Polish
Resistance fighters
died fighting against
German forces.

14. Reasons the Cold War started
The USA and UK supported
the resistance through
an airlift of supplies.
However the USSR stopped
at the edge of Warsaw
and would not send in
forces to help the
Poles. They also would
not allow Soviet
airports to be used to
support the airlift.

15. Reasons the Cold War started
The USA and UK believed
that the Soviets did
not intervene because
they wanted to remove
the resistance that
might oppose Communism.
This suggested that the
USSR planned to take
violent control of
Poland after the war,
creating tensions.

16. Reasons the Cold War started
However Stalin claimed
that his army were not
ready to fight and
needed to rest.
Also, in spite of this
argument, the USA, UK
and USSR kept fighting
on the same side,
undermining ideas that
these events led to
Cold War.

17. Reasons the Cold War started
By late 1944, it
seemed obvious that
Germany was going to
lose the war.
The so-called ‘Big
Three’ of the USA,
USSR and UK were
already planning for
what would happen
after the war ended.
This led to arguments.

18. Reasons the Cold War started
The first major
meeting between the
three countries took
place in Tehran in
Iran in 1943.
There were later
further meetings
between each country’s
leaders in 1945: Yalta
in Ukraine and Potsdam
in Germany.

19. Reasons the Cold War started
These meetings –
especially Yalta and
Potsdam – showed a
huge divide between
the three allies.
In particular, they
could not reach
agreements about what
to do with Poland and
Germany.

20. Reasons the Cold War started
The Soviet Union wanted control of Poland.
In both World Wars One and Two, Russia had
been invaded by Germany. Therefore they
wanted to use Poland as a ‘buffer zone’ to
stop this happening again.

21. Reasons the Cold War started
However the USA and UK
wanted Poland to be a
free country, with
elections to choose
its own government.
Britain went war in
1939 after Germany
invaded Poland (the
Soviet Union later did
the same, in agreement
with Germany).

22. Reasons the Cold War started
Disagreements about
post-war Europe caused
the Cold War because
they exposed the
different beliefs of
the USA and USSR.
The Soviets felt their
wartime sacrifices were
not being respected if
they did not get a
‘buffer zone’.

23. Reasons the Cold War started
However both sides did
in fact reach
agreements at the
Potsdam meeting.
This shows that each
side did not allow
their differences to
stop them working
together, suggesting
this is not a reason
the Cold War began.