[bryanlarsen]

Even deliberate nuclear use might not trigger a nuclear response.

They've kept strategic ambiguity, but it's obvious that the US has developed a plan (or several plans) on how to react if Russia drops a nuke on Ukraine. And it seems clear that the US feels they can make Putin and Russia regret the use of nukes without using American nukes in response.

[NoMoreNicksLeft]

It's plausible that we could make them regret it. If the US simply entered the war on Ukraine's side, Russia's options are to wait patiently to be curb-stomped, or to escalate... and I don't think they could imagine that the US wouldn't retaliate disproportionately.