[Goose]

Because Russia is un-invadable for both nuclear and logistic reasons, what "victory" likely entails is pushing the Russians out of Ukraine and hopefully Crimea. Of course, that would not stop russian missle or long range fires over the border, so for the war to truly end there needs to be some form of russian acceptance.  My preferred approach would be to use western aid to push the russians out of ukraine, and then set up an internationally secured border a la Korean DMZ. It can be made clear that long range fires from Russia into Ukraine, including those that target western forces, will be responded to in kind.

I think you are basically on the right track. However, to be clear, the Korean DMZ is not internationally secured. It is secured by South Korea and the US. In theory, the UN could attempt to organize a force to do so, but it is highly probable that China, Russia, or both would veto that. It wouldn't matter anyway, as by the time such a force was created it would be all over. If we are lucky, we could get NATO participation for such a "DMZ" in Ukraine, but in fact it will be the US and Ukraine that must provide the legitimacy of the border.

Crimea is a sticking point for Ukraine. While it can be argued that it isn't "organic" to Ukraine, keeping the Black Sea available to Ukrainian traffic pretty much requires that it be Ukrainian. If it isn't, Russia can close the Sea of Azov from their own land borders. That kind of defeats a DMZ. The presence of Russian naval forces in Crimea also greatly hampers keeping a lid on confrontations between Ukraine and Russia. I don't think a  solution giving Crimea to Russia will work. Possibly making the whole of Crimea part of the DMZ and governed as an international entity might work, but sounds pretty undesirable for anybody living in Crimea (unless there were no taxes :-). Not an easy problem.

[Goose]

Because Russia is un-invadable for both nuclear and logistic reasons, what "victory" likely entails is pushing the Russians out of Ukraine and hopefully Crimea. Of course, that would not stop russian missle or long range fires over the border, so for the war to truly end there needs to be some form of russian acceptance.  My preferred approach would be to use western aid to push the russians out of ukraine, and then set up an internationally secured border a la Korean DMZ. It can be made clear that long range fires from Russia into Ukraine, including those that target western forces, will be responded to in kind.

I think you are basically on the right track. However, to be clear, the Korean DMZ is not internationally secured. It is secured by South Korea and the US. In theory, the UN could attempt to organize a force to do so, but it is highly probable that China, Russia, or both would veto that. It wouldn't matter anyway, as by the time such a force was created it would be all over. If we are lucky, we could get NATO participation for such a "DMZ" in Ukraine, but in fact it will be the US and Ukraine that must provide the legitimacy of the border.

Crimea is a sticking point for Ukraine. While it can be argued that it isn't "organic" to Ukraine, keeping the Black Sea available to Ukrainian traffic pretty much requires that it be Ukrainian. If it isn't, Russia can close the Sea of Azov from their own land borders. That kind of defeats a DMZ. The presence of Russian naval forces in Crimea also greatly hampers keeping a lid on confrontations between Ukraine and Russia. I don't think a  solution giving Crimea to Russia will work. Possibly making the whole of Crimea part of the DMZ and governed as an international entity might work, but sounds pretty undesirable for anybody living in Crimea (unless there were no taxes :-). Not an easy problem.