AIUI, the consensus thinking seems to be that even if Russia decides to employ nukes in Ukraine, they're not necessarily the "trigger mass retaliation and cause

AIUI, the consensus thinking seems to be that even if Russia decides to employ nukes in Ukraine, they're not necessarily the "trigger mass retaliation and cause a nuclear winter" type. Apparently they have "tactical nukes" that are much (much) less powerful (in terms of yield) than the ones tipping the ICBM's and that figured in "War Games" etc. Now, would even using something like that trigger a response from other nations, and could it still escalate to "Global Thermonuclear War"? Probably. But at least in the short-term it doesn't appear to be the case that as soon as Putin "pushes the button" it's automatically game over for everybody. Also, supposedly three people are required to use even those nukes, with Putin being one of the three. There seems to be some thought that the other two might refuse to allow their use. How Putin would respond to something like that is an interesting question. Given the unrest over the Russian draft, I can't help but wonder if all of this is leading to a possible regime change in Russia.