> Did they really launch this invasion on the assumption that the people of Ukraine would just roll over and accept foreign rule?

I don't think it's that simple.

Sure, conscripts were told to expect a welcome in streets lined with natives waving Russian flags. Maybe some in high command even thought that was a possibility. But they have backup plans; we've seen only the first click of the ratchet. Escalate, pause; escalate, pause. This happened in Chechnya too.

Putin didn't invent this approach. And Putin didn't invent the idea that Ukraine is not a separate state, but a part of Russia.

He's written history books, I gather; I might be interested in reading one, but I suspect they're hard to get hold of just now.