[Its All Over Except ...]

Difference is, Hitler could roll over all Europe, and Putin won’t attack a MATO member.

[nicollo]

You made the correct point in response. Exactly.

[BroJoeK]

"Difference is, Hitler could roll over all Europe, and Putin won’t attack a MATO member."

Which sort of explains, doesn't it, why Ukraine and every other country near Russia's borders will need to join NATO or some other defensive alliance?

Hitler "rolled over all Europe" because he believed, largely correctly, that those countries were too weak to stop him.
Russians won't attack a NATO country so long as they believe NATO is strong enough to defeat Russia.
That's why so many countries near Russia want to join NATO, if they haven't already.