[81alum]

Another way of thinking about it....what would the response have been to Saddam Hussein's invasion of Kuwait if the world was sure he had nuclear weapons at that time?

Not much different. Saddam Hussein did not have the ability to deliver nuclear weapon reliably anywhere outside of the immediate area, if that. North Korea fully understands this. That is why they have worked so hard to develop a credible delivery system. Russia OTOH has the ability to reliably deliver fusion weapons (a much more damaging weapon class) anywhere on the planet in large numbers. These numbers could (probably would) bring on a "Nuclear winter". Nobody could reasonably expect to "win" that war. While it is horrible that N. Korea has a nuclear capability, it is nothing at all compared to Russia. A nuclear exchange between the US and Russia would be many orders of magnitude worse. The downside of this magnitude simply can't be ignored, like it or not.

Well my counterfactual, hypothetical thought experiment...suppose he was known to have nuclear weapons and the capability of delivering them reliably as far away as Israel?  Would our response have been the same?  To risk the utter destruction of Israel for the liberation of Kuwait? 

Having nukes always changes the calculus of the other side, and having a LOT of nukes as Russia has, changes the calculus in the way you expertly describe.  This puts US Foreign policy with respect to Ukraine in a kind of moral dilemma:  we must balance doing the just thing (helping Ukraine) with the risk of enormous harm to civilization.  Given that war is littered with miscalculations and irrational decisions, the risk of nuclear escalation  has to be taken seriously, and that puts a different cast on the war in Ukraine than on our much more vigorous response in Desert Storm.

Have we been too timid?  Probably.  But we could probably keeping saying so right up to the tipping point, and we can't afford to be wrong even once.

[81alum]

Another way of thinking about it....what would the response have been to Saddam Hussein's invasion of Kuwait if the world was sure he had nuclear weapons at that time?

Not much different. Saddam Hussein did not have the ability to deliver nuclear weapon reliably anywhere outside of the immediate area, if that. North Korea fully understands this. That is why they have worked so hard to develop a credible delivery system. Russia OTOH has the ability to reliably deliver fusion weapons (a much more damaging weapon class) anywhere on the planet in large numbers. These numbers could (probably would) bring on a "Nuclear winter". Nobody could reasonably expect to "win" that war. While it is horrible that N. Korea has a nuclear capability, it is nothing at all compared to Russia. A nuclear exchange between the US and Russia would be many orders of magnitude worse. The downside of this magnitude simply can't be ignored, like it or not.

Well my counterfactual, hypothetical thought experiment...suppose he was known to have nuclear weapons and the capability of delivering them reliably as far away as Israel?  Would our response have been the same?  To risk the utter destruction of Israel for the liberation of Kuwait? 

Having nukes always changes the calculus of the other side, and having a LOT of nukes as Russia has, changes the calculus in the way you expertly describe.  This puts US Foreign policy with respect to Ukraine in a kind of moral dilemma:  we must balance doing the just thing (helping Ukraine) with the risk of enormous harm to civilization.  Given that war is littered with miscalculations and irrational decisions, the risk of nuclear escalation  has to be taken seriously, and that puts a different cast on the war in Ukraine than on our much more vigorous response in Desert Storm.

Have we been too timid?  Probably.  But we could probably keeping saying so right up to the tipping point, and we can't afford to be wrong even once.