“Gorbachev’s reasoning could partially be explained by the domestic dilemma he faced: how could he tell the Politburo that he had asked for written guarantees that NATO would not expand to the territories of the Warsaw Pact while the Pact was still in existence? That would have meant he had already accepted the idea that the socialist alliance was on its deathbed”

A good diplomat might have phrased that differently, without removing too much content, though, so that the Warschau pact wouldn’t lose face from it. Maybe something along the lines of that the two parties recognized each other’s spheres of influence? (Or maybe that wasn’t something either party was willing to commit to?)