I think that this "concern" is the reason why this war is actually taking place. If NATO countries would have told that intervention is not out of question and invasion is not acceptable then Russia would have moved its forces back into their barracks after exercises.
When the risk is nuclear war, that is not good enough. No no-fly zone, no hot war between nuclear powers. We are already risking way too much. The expected value of a 1% increase in the odds of a nuclear war is somewhere around a million casualties.
The world is precariously close to returning to "might makes right". That is the recipe for world wars. Not "he cannot remain" comments.
The two world wars are in the vicinity of 100 million deaths, direct and indirect. This is why the judgement of Nuremberg was that wars of aggression, i.e. wars of conquest to expand borders and/or subjugation, are the supreme international crime. This is how the League of Nations and United Nations was formed. The reason why this particular invasion is a big deal is because it's once again (a) in Europe and (b) rolling tanks into a sovereign nation. This is perhaps worse because Russia is a party to two treaties that say Russia will not do exactly what it is doing, and to this particular country.
So we are well past the point the WW2 generation had learned was the hard stop.
We're confronting the real possibility that nukes are a better deterrent against aggressive war than the UN. And the unwinding of the UN system, which would surely extend to the NPT. And at that point it's proliferation.
In 1994 Poland insisted on joining NATO or else they were going to develop their own nuclear weapons program, because they didn't trust Russia. They weren't alone.
We might be doomed. We can't directly attack Russia out of fear of a nuclear war. We can't appease by accepting a surrender.
> The world is precariously close to returning to "might makes right".
This paradigm never left us, you (and I) are just on the team with the most might at the moment.
> We can't appease by accepting a surrender.
Again, on what basis? Because you say? The term appeasement was popularized before the existence of the existential nuclear threat, and it is not a certainty that diplomacy will lead to the same outcome as starting a hot war between nuclear powers.
We might be doomed, certainly. But we might not be, and the option currently pursued by NATO (aside from some incendiary slip of the tongue about regime change in Russia) is, thankfully, to not pursue direct conflict with Russia for this reason.
>This paradigm never left us, you (and I) are just on the team with the most might at the moment.
It is contrary to the international legal system. And it's thoroughly argued against by Socrates versus Thracymachus.
>Again, on what basis?
On the basis of UN Charter article 2(4) and (5). Surrender means (4) is set aside if in fact you can start a war of aggression and come out ahead. That is completely untenable in the international institutions that exist right now. And willingly setting aside (4) means (5) has also been set aside. The Charter isn't some aspirational document, it is a treaty countries are legal parties to insofar as their sovereignty was used to acknowledge its truth and their agreement to be bound to it.
141 countries agreed to UN General Assembly Resolution ES-11/1. Russia must withdraw from all of Ukraine. It is in the interest of most countries to agree to this resolution, because it is one of the easiest calls to make since the UN was founded, and why it was founded.
If the UN unravels... humanity has no institutional means of stopping another world war.
> It is contrary to the international legal system
> On the basis of UN Charter article 2(4) and (5) [...] Russia must withdraw from all of Ukraine
> If the UN unravels...
The US and Russia routinely violate international law. The UN is not capable of enforcing these laws against actors like the US and Russia. We may not like it, but might continues to make right.
