During the Cold War, the Soviets were absolutely convinced that NATO, particularly the United States, was more than willing to initiate a First Strike without warning. This paranoia fed into their reaction to Able Archer '83, where they thought a NATO wargame involving heads of state and the theoretical use of nuclear and conventional weaponry to be a disguise for an actual first strike and invasion.
I'd say the mental calculus that formed those opinions has probably changed since the end of the Cold War, particularly in regards to the current administration and military leadership. We have the head of the Joint Chiefs supposedly telling China he's going to fucking warn them if we attack. I don't think Russia or China fears a first strike response from us and that very well might tie into any nuclear option they might take to further their goals.
I will say that I
sincerely doubt either nation is interested in detonating nuclear munitions in city centers. That is an open invitation to have your own city centers attacked, which is something neither side can accept. You would see nuclear strikes on carrier strike groups or on overseas bases long before you'd see any ICBM flung anywhere near the continental United States. One airburst over Moscow, Beijing, or Los Angeles would be enough to effectively cripple the warfighting capability of any of these nations. I pulled the following example from NUKEMAP:
View attachment 2643703
If I'm the Chinese and I airburst an ICBM somewhere around Los Angeles, you can see the estimated fatalities and injuries above. Even if you take out the overwhelming number of dead, the injured will cripple the supply chain and healthcare systems of the United States. There will be more burn victims requiring specialized burn beds than there are burn beds
on the entire planet. The United States (or China or Russia) would be completely incapable of engaging in a conventional war while also responding to a disaster of this scale. Vaporizing large urban centers is something that could cause an entire nation to fall on its own.
Using a tactical nuclear warhead on a carrier group or armored column is one thing - that's a national disaster, but not fatal for that nation. Nuking a city overwhelms that nation's ability to respond to that nuclear strike on a humanitarian level, much less engaging in conventional warfare. You've essentially just cucked yourself into guaranteeing a counterstrike on one of your own major urban centers, because what other option would the United States have in this example? If you lose an amphibious group crossing the Taiwanese Strait, you still might come out ahead in some fashion after the war ends. If your capital goes up in a ball of yellow fire, it doesn't matter how many cities you've nuked off the map, because you've still fucking lost.
