The point is it doesn’t. Ukraine is on its way to wiping out Russia’s Black Sea Fleet. It’s pure posturing to pretend Moscow is stupid enough to end its existence over a naval battle, much less simply credible threats of one.
That statement doesn't really amount to much given the risk. I think we need something far more convincing; and many experts clearly think nuclear war is a risk.
Is this correct?
Look up what they said would trigger a nuclear war at the start of the invasion. Many of those things have already happened.
Also, Biden vary carefully managed that risk by slowing boiling the frog. Too carefully, I thought, but it's reasonable that his overwhelming priority was preventing nuclear war.
Yes, Russia is the problem, but that's not really relevant (or, frankly, mature). The situation is what it is, and we must decide how to get the best outcomes.