maybe I’m naive to belive he will stop at the donbass and crinea but I do believe that. Right or wrong then two areas are now lost to Ukraine and Russia this war will become unsustainable to finance and in the end Ukraine will have to settle for a deal cecedibg land to Russia .See the issue here is you believing Putin, and by extension Russia, are amenable to the effects of diplomacy. We're talking about a terrorist state that has now inflicted suffering and claimed the lives of hundreds of thousands of people. We're talking about a gangster that rigs elections and kills political opponents that are a threat to his demagoguery. He poisons expats on other nations soil; remember Litvinenko? Just last week a children's hospital was bombed on the orders of this ****; do these people deserve diplomacy, or do they forfeit the right to diplomacy? Putin is a Peter the Great obsessive who wants a return to a soviet empire, he wants all Slavic peoples and their sovereign nations under a Russian umbrella.
When the wall fell, Russia was on course to be democratised and embraced by the West. Putin has eroded all that goodwill with his insecurity and Russia has subsequently regressed to its hitherto pariah state. I highly recommend a book called The New Tsar, it details just how gravely Russia has regressed as a nation over the last twenty years: the sole reason is Putin.