I don't personally believe it. I think that Putin, like Stalin, is a hoodlum and a rat, like the previously mentioned Kray Twins. If he thinks the opposition is weak he will go toe to toe and push as hard as he can but, if the opposition looks like it might win or even draw, he will choose survival and living to fight another day. Hitler was altogether a different character, a 'Messiah' complex that required an all or nothing outcome.
Hitler fought with every German citizen at his disposal until all was lost then blew his brains out rather than risk being taken alive but when Stalin thought all was lost he sat blubbering until his cronies, a bunch of degenerates, scum and paedophiles gee'ed him up to carry on. Putin is a Stalin, not a Hitler.
It's my belief that, as long as Putin is met with little more than grumbling he will continue to roll forward. His bluff needs called and his ass needs kicked. The best thing of course would be for the Russia masses to have a new revolution and put him and his cronies down but, if that doesn't happen and we don't stand our ground then he will take it too far and all out war will be the only result.