The cold War probably started in 1918 when the US invaded the Soviet Union to try and foment a counter revolution. Immediately after the end of WW2 the US and Great Britain began to try to undermine the soviet union. The point is that the starting point for the cold war goes back to The western powers distaste for any systems of government that didn’t allocate natural resources to them. To put a more precise date on it one might say when Churchill gave his Iron Curtain speech in Missouri in 1946 but it was based on proclivities that were apparent long before then.
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