escalating is very dangerous

One can always justify defending oneself. It's quite another thing to strike deep into Russia. That becomes a potentially existential threat to Russia, which could result in the war escalating to the use of tactical nuclear weapons on pilling beyond the borders of the combatants to neighboring countries. And that, my friends, is how Wold War III starts.

As the famous Einstein quote goes, "'I know not with what weapons World War III will be fought, but World War IV will be fought with sticks and stones."