How do speakers explain the same turning point in different ways?

How do crisis explanations mark the limits of their evidence?

In his 2015 lecture, John Mearsheimer names NATO and EU expansion and Western democracy promotion as deep causes of the Ukraine crisis, then argues for a neutral Ukraine. In his 2018 Yale lecture, Vladimir Pozner also treats NATO expansion as a turning point in deteriorating US–Russia trust, while discussing post-Soviet policy choices and media narratives. In the Q&A, he calls some of his claims opinions and acknowledges that a counterfactual about a different US policy cannot be proven. The lectures overlap in attribution but differ in scope. Compare their historical causal claims, policy proposals, and unrealized counterfactuals separately; neither speaker’s account is established by the lecture alone.