

True. Problem is: how do you respond to someone that use a nuke ? If Russia use a nuke, it is the end either way: if other retaliate the situation escalates, if they do not retaliate Russia think they have free hand.
During the cold war the only thing that prevented a nuclear escalation is the certainty of mutual destruction, nothing else.



True, but probably they are more than the ones EU can send.
From a pure logical point of view you are right, but in reality there is nothing that prevent him to do it. Which do not imply that he can win obviously, he just need to be able to go on longer than EU.