1. That depends on a number of reasons, for example how far such an attack would go.
2. That all depends on a number of premises and interpretations. I see no reason to doubt that Russias business community and the majority of its people prefer to build their country, trade and travel instead of a confrontation that would be to nobodys benefit. And you should also see that Putin is among others the man of big business in Russia. The oligarchs that are backing him would be the first to loose enormous amounts of money in that case. And support for him also has to a large extent economic reasons regarding ordinary Russians. His governement is already for that reason unlikely to make any such moves towards western Europe.
And western european militaries are in a period of transformation and restructuring ( for example through forming european army structures). That is not the same as decay.