The Allies declare war on the Soviet Union in 1939

Nov 2013
586
Kingdom of Sweden
What if, when the Soviet Union invaded Poland on 17 September 1939, France and the United Kingdom declared war on the Soviet Union in their defense just as they did against Germany? How would the war progress differently with the Soviet Union and the western Allies on opposite sides? How long would the Soviet Union and Germany remain on the same side against a common foe? And when or if a German-Soviet split happens, will there be any chance for Britain and the Soviet Union to reform their alliance? And finally, how would such a war end?
 

Futurist

Ad Honoris
May 2014
23,774
SoCal
If Britain and France are stupid enough to do this, then it's possible for Nazi Germany and the Soviet Union to form a military alliance with each other. In such a scenario, I wonder if Stalin would offer--and if Hitler would accept--Soviet troops being sent to the Low Countries and France in order to help the Nazis fight the Western Allies.
 

stevev

Ad Honorem
Apr 2017
3,759
Las Vegas, NV USA
When the USSR invaded Finland in 1939, Churchill wanted to act so it's not out of the question. Chamberlain was still PM and the UK was already at war with Germany, so nothing was done about it. The "Phony War" ended in May, 1940 and France fell. So this alternative scenario would have to happen as soon as the USSR invaded Finland. For any possibility of success, another ally for Britain and France is needed. Japan was no friend of the USSR having suffered a defeat in Mongolia (Khalkhin Gol). Despite its loose alliance with Germany, Japan could divert Soviet forces to east Asia. It would have had to call off its war with China or better, never have started one. Even a Chinese alliance with Japan against the USSR might have been possible. Under these circumstances Britain and France might have a fighting chance against the USSR + Germany. Having Japan as an ally protects British possessions in the Far East at least until the next war.

Although the USA might seem like an obvious third ally, it was militarily weak and isolationist in1939. I know this scenario seems far fetched but so are the assumptions given.
 
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Chlodio

Forum Staff
Aug 2016
5,015
Dispargum
Perhaps the greatest contribution the Soviets could make to a war against Britain and France was naval. The Soviets had aprx 200 submarines. Forward those to German bases in 1939/40 and lookout Britain.
 

stevev

Ad Honorem
Apr 2017
3,759
Las Vegas, NV USA
Perhaps the greatest contribution the Soviets could make to a war against Britain and France was naval. The Soviets had aprx 200 submarines. Forward those to German bases in 1939/40 and lookout Britain.
Yes, but in my scenario, the USSR would need its naval assets to fight Japan.
 

Futurist

Ad Honoris
May 2014
23,774
SoCal
Although the USA might seem like an obvious third ally, it was militarily weak and isolationist in1939. I know this scenario seems far fetched but so are the assumptions given.
This can be changed if the U.S. enters the League of Nations with reservations and also ratifies the Security Treaty with France back in 1919-1920.
 
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stevev

Ad Honorem
Apr 2017
3,759
Las Vegas, NV USA
This can be changed if the U.S. enters the League of Nations with reservations and also ratifies the Security Treaty with France back in 1919-1920.
Perhaps, but there's a reason the US didn't enter the League. The people were fed up with perceived devious self serving European intrigues. They still remembered Washington's admonition to avoid foreign entanglements. This was a bottom up, not top down sentiment. Even Coolidge was more of an internationalist than the average voter. Anyway in 1939 American troops were training against delivery trucks with the word "TANK" painted on them and aiming wooden rifles at them. It would take Pearl Harbor to get the US into WWII. The Battle of Midway could easily have been lost. It was by chance that US dive bombers came upon the main Japanese carrier fleet at just the right time.
 
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