Here’s another fine example of that era:
The MolotovRibbentrop Pact, also known as the NaziSoviet Pact or the GermanSoviet Non-aggression Pact (officially: Treaty of Non-aggression between Germany and the Union of Soviet Socialist Republics), was a neutrality pact between Nazi Germany and the Soviet Union signed in Moscow on 23 August 1939 by foreign ministers Joachim von Ribbentrop and Vyacheslav Molotov, respectively.
https://en.wikipedia.org/wiki/Molotov%E2%80%93Ribbentrop_Pact
good point. One would think people would learn form history, but alas, it seems not.
In that case it wasn’t so much a matter of a knife in the back but whose knife and whose back would be first.