I don’t think, as long as the continental US isn’t hit, that we would respond with a launch on Russia.
If we launched against Russia, and they did the same, we are all done for. Neither side has the ability to intercept all. I think if the Russians used a tactical weapon, our bluff would be called. And we would fold, I think.
you are thinking in a rational strategic framework. Nothing I have seen so far suggests such thinking is applicable here.
we are baiting them to start world war 3. our rulers’ goals are not rational by our definition - the US does not have an interest in a world war over the former Ukraine SSR.
they need a major war to try to stay in power, even if it wrecks us.