Today we know that when the Nazis invaded Poland in 1939 they left the entirety of West Germany completely unguarded. The British and French could have marched unhindered right up to Berlin. But they overestimated the Germans, stayed behind, and Poland fell. We are doing the same thing again.
Comments
Considering the state of russia's economy my preference would be the EU confronting russia in eastern Ukraine. This way russia is defeated by an economic collapse.
https://en.m.wikipedia.org/wiki/Saar_Offensive
https://en.m.wikipedia.org/wiki/Dunkirk_evacuation