No, Putin will settle for as little as a third. He'll get Crimea, the Donets, and Kharkov. He MAY take the lower Deniper and the area to the east and South. He won't go beyond Kiev or go for the former Polish territories.
Putin will go where ever he wants. Who is going to stop him? Democrats in Washington? Bwaaaaaaa!!
A lot of their Ukraine isn’t worth having. The Donets is like Detroit or the bad parts of New Jersey, a social service spending sink, a rustbelt with lousy prospects. I don’t think Putin wants those parts.