Indeed. Some things are different today. Nukes, cyber weapons, NATO borders being tougher than the League of Nations, the imperial country having a weak economy, and the whole thing is a war without a cause.
Russia invading a NATO country would be akin to walking on a landmine. Putin's not a fool, so it is very unlikely to happen.
Well, he could've led Russia on the same path as China, making it a true world power that other countries massively depend on. Instead the fascist government chose isolationism. So, the foolishness of Putin is quite debatable.