>>...successive American presidents and European Union diplomats have expanded NATO and the EU into former communist states.

But that's not what happened.

Those former states determined they no longer wanted to be part of the 'rump' USSR, and fled into NATO. About the only charge that can be laid against the US is that they, as a NATO member did not block entry of those nations, as any NATO member can (e.g. Turkey blocking Sweden and Finland for their own purposes which I won't get into here). It's pretty clear that France did some maneuvering as to getting nations into the EU so as to build a voting block. but the EU and NATO are different organizations (and France has repeatedly tried to torpedo NATO, IMO same motivations)

As far as historicism (the notion of inevitability, or even just predictability of societies) it's worth reading Popper's "Poverty of Historicism", as it seems clear Snyder has.

Disclaimer: I'm more of a geographical determinist (in sense of productive agricultural acreage, length of transport networks, defensible borders) as regards a nation's wealth. Political system, not so much.

All that said, liberal democracy seems to have failed people in the middle class and below. I see that as capture of the government by the moneyed class (and in the US, a deliberate sacrifice of manufacturing in order to rebuild post WWII - and a bribe to keep recovering nations out of the Sov orbit). That capture might be one of the weaknesses of democracy, but it doesn't mean democracy will proceed inevitably to something else. It just means there's a need for safeguards (e.g. TR post Gilded Age).

PS: congrats on a first article!