There's a trend where a nuclear attack on Russia is being encouraged as a response to invading Ukraine? Or am I misreading your first sentence?
https://www.reuters.com/world/us-cannot-take-lightly-threat-...
Either because they think that a nuclear escalation won't happen, or, more concerningly, because they think that a nuclear escalation is something that they can win.
Of course NFZs have to be enforced to actually be NFZs and that means NATO shooting down Russian jets/helicopters/missiles that violate the NFZ. This would be a direct attack by NATO forces on Russian forces.
Such an attack, would give the Russian's a legitimate "out" for attacking NATO forces (say in Poland) where a lot of refugees and material is being shipped through to Ukraine. That would trigger Article 5 which says, briefly, "an attack on one is an attack on all." and we would be in a full hot war with Russia.
At that point, Russia can legitimately claim they "feared for their existence" and launch a nuclear strike (tactically or globally) against NATO countries (including the US) and that ends up with the US and Russian destroying a lot property using nuclear weapons.
There is an argument being made that Putin desperately wants to get attacked by NATO so that hey can threaten nuclear war, and cause NATO to back down. It certainly looks better at home if Russia is on the ropes because NATO is attacking it rather than being on the ropes because a former satellite state of the old USSR is handing it it's ass on a platter.
There is a lot riding on the outcome of the current conflict and it reached a point, quickly enough, that I believe it will reshape geopolitics for decades.
Throughout the Cold War there were people, on both sides, who felt "we could win such a war." Their definition of "winning" was somewhat twisted (as a full out war would result in knocking the world into a very very bad place civilization wise) and it was the subtext of the movie Dr. Strangelove. We have been exceptionally fortunate that we haven't tested their theories. I am, somewhat obviously, in the camp that full on nuclear hostilities would reduce the planet to a population of perhaps one or two million humans, mostly in South America and the Pacific island nations. But I am not anywhere close to being an expert on these things, just a systems analyst type.
So my observations have been:
Call: "We should go in there an kick the Russian's asses."
Response: "We won't because that would start a nuclear war, and we don't want that."
Response: "What if we would 'win' the resulting Nuclear war? Still not going to go kick there asses?"
If you watch any sort of "large conversation" like this, where part of a group wants some action and another part of the group doesn't want that action, you will see this sort of interplay. It happens in companies, it happens in counties, states, countries, and the world at large. Various voices attempting to achieve a sufficiently high level of consensus from the group in order to take an action. Failing to achieve a high enough level consensus results in "group antibodies" which are basically people who become so offended at the action proposed the switch to becoming active members of resistance and start trying to generate counter action consensus.
I have exploited this effect to create change in large organizations that were stagnant. You start by pushing just enough on the change to 'surface' the people who had been acting through intermediaries to act directly. Then you can identify them and have a one on one conversation to get them signed up for the change. Do that enough times to surface all the resistance, and then at some point the change just "goes through" because "everyone seems to think it is the right thing to do."
No, that's not actually the issue.
The issue is that the usual method of NFZ enforcement means preemptively destroying Russian air defenses first, to make it safe for aircraft patrolling the skies to find and intercept aircraft that might violate it.
Of course, at least one NATO member (e.g., Poland) has gone beyond calling for an NFZ to call for NATO peacekeepers on the ground for various purposes.
NATO’s Eastern flank is not super happy with waiting for Russia to attack them, given their demonstrated aggressiveness and rhetoric tied to historical imperial Russian territory.
Related: I usually find these conversations kind of gliding around what I think is the primary point. There's the military tactics, gambles, and trade-offs; and the immediate and long-term effect on societies; but I feel like it's usually kind of glossed over that 10s of millions of civilians will die. It's one thing to talk about putting the lives of your army on the table, and gamble on how long it will take for society to catch back up to where we are, but it's quite another thing to put entire civilian centers on the table. Of course, I really have no idea how far Russia, or anybody, would have to go to make that gamble worth it. Putin's threats of the nuclear murder of millions of innocent people for the "crime" of participating in the war he started essentially puts NATO in a much larger-scale version of the "negotiating with terrorists" situation. I've never been so unsure as to what the proper level of response is.
All that blob of text is pointless. NATO need merely declare it has no offensive ambitions. Which it doesn’t. Then there’s no existential threat.
Whether Russia chooses to use nukes, likely against kyiv, is really independent of that distinction. Whether the west responds with nukes is all but assuredly “no”.
Yet the bully also knows if they actually use the gun they'll be put down like a feral dog before they have time to reload.
Let's examine that from a counterfactual standpoint. Let's say that during the invasion of Iraq Russia had decided to impose a no fly zone and then proceeded to shoot down American aircraft when they violated it. They of course declared that they have no offensive ambitions, they're simply helping to defend a sovereign nation against a larger aggressor. Would that have caused the United States to attack Russian forces?
That is part of the reason why there are college courses dedicated to the topic, pages and pages of historical analysis of the choices made in situations in the past their their outcomes, analyses of the issues leading up to the "fulcrum point" of the crisis, and daily assessments (guesses) of the mental state of, and the response of, the key players in the situation.
That these situations are not popping up every day is a testament to the work of a functional state department and diplomatic corps. And it is why the people in that corps who heard a President extorting a foreign leader by withholding military support in exchange political favors, were so horrified.