Why did the allies declare war on Germany but not the Soviet Union when they both invaded Poland in September 1939? And why did they give up Poland to the USSR after the war when they initially entered the war to protect Polish indepence? | AskHistorians Archive Observer

Why did the allies declare war on Germany but not the Soviet Union when they both invaded Poland in September 1939? And why did they give up Poland to the USSR after the war when they initially entered the war to protect Polish indepence?

by BeardedApeGuy

scarlet_sage

You may be interested in these answers from the FAQ section "Soviet-Polish Relations" .

"Why is that only Nazi Germany is condemned for invading Poland while the Soviet Union also annexed a large portion of Poland and committed nearly half a million troops?" by /u/kieslowskifan . This touched on the 1939 question.
"Why did England and France only declare war on Germany while Russia invaded Poland too?" by /u/Balnibarbian . This touched on the 1939 question also in other aspects.
"Why did the Western allies cede so much of eastern Europe to the Communists?" by kieslowskifan covers the post-war question.

But this is not to discourage more questions, data, or debate.

BeardedApeGuy

Thank you, sir.