[BroJoeK]

higgmeister: "Have you not heard of MAD, Mutually Assured Destruction?
If the super powers use nuclear weapons there is no choice but to launch on warning."

The basic idea is, if Russia attacks Ukraine with nukes, then Russians can expect to be attacked with nukes in return.
Tactical nukes?
Strategic nukes?
Nuclear engineering devices?
Who knows?

Vlad the Invader can expect that whatever he launches at Ukraine, Russia will receive in return.
How MAD is that?

[Alas Babylon!]

Russia using nukes only on Ukraine would get a whole new level of global condemnation and the loss of Chinese support, but would not cause the US to respond with nukes. That would be suicide for us.

We do not have an obligation to trade Kiev for Washington.

We do have an obligation to trade Moscow for Washington (and a thousand other places). The British and French have their own nuclear forces they could use separately, that is, not controlled by the United States. I think the British would rely on the US to decide, but France would absolutely launch if Paris was obliterated.

We would only launch ours if they launched a nuclear attack against us or NATO. That’s where mutually assured destruction (MAD) comes in.

[griffin]

Really?
US has no TacNucs any longer.