Imagine Trump threatens to nuke Russia if they don't leave Ukraine tomorrow, according to your logic they shouldn't run the risk of a nuclear exchange and Russia should retreat.

Is this correct?

Spot on. Recognising Putin’s fake lines normalizes a nuclear response to conventional tactics. That path opens to a future where it would be irrational not to constantly threaten nuclear holocaust for minor military advantage. And in that world, someone will eventually miscalculate.

And Russia could threaten to nuke the US unless the US surrendered Poland. Obviously, the hypotheticals are absurd and flawed.

> many experts clearly think nuclear war is a risk

Look up what they said would trigger a nuclear war at the start of the invasion. Many of those things have already happened.

They said it was a risk. The fact that it didn't happen doesn't disprove that. A 1/100 risk of nuclear war almost certainly wouldn't happen, and would be far too high of a risk.

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.