[mrjin]

I seriously doubt US will directly engage Russia if Ukraine get nuked as it's simply doesn't make sense per the "America First" or now "America Only" playbook.

The only question really should be whether Putin dare to nuke Ukraine, if he indeed go there, end of story.

[EdwardDiego]

US isn't the only player with nukes though.

[mrjin]

That's exactly why US doesn't want to get involved directly.

[EdwardDiego]

I wonder what China would do if Russia took things nuclear. They seem happy to watch Russia and NATO weaken each other, but I'm assuming they like a reasonably stable world, given their dependence on trade earnings for internal stability.