For weeks now the war has appeared to drag on with protracted fighting and a slow-moving front.
Russia's attempt of taking Kyiv and replacing the government has failed, and given the Ukrainian resolve and Western support it seems unlikely that they will be able to do so in the future. Consequently they are concentrating their military efforts in the East and in the South where they try to extend the occupied area.
Conversely, it seems unlikely that Ukraine will be able to restore the borders of 2021 or reconquer Crimea.
The goals of the involved parties are, in a rough outline:
Ukraine's immediate goal is to prevent Russian advances in the East and South. That goal appears realistic but is not a given. The long-term goal to re-establish control over its entire territory appears unrealistic. The best military outcome appearing realistic right now is to to re-conquer some places and prevent Russia from advancing elsewhere. The worst outcome is a protracted war with even more territorial losses.
The Russian goal to establish permanent control over Ukrainian territories in the East and South seems in principle realistic, although the precise territory is still to be defined, by whatever means. The result may be a larger or a smaller territory than the currently occupied area.
The Western goal is to prevent the aggressor from succeeding. A secondary goal is to weaken Russia's military. While the latter is realistic, the former is rather not: Even with massive deliveries of heavy weapons it is unlikely that Ukraine's borders of 2021 will be restored with military means in the near future.
This seems to naturally lead to cease-fire negotiations that would determine a "line of actual control" close to an eventual realistic military outcome but save thousands of lives, let alone property and resources. Of course, the "eventual realistic military outcome" is pretty fuzzy. A cease-fire would define a line of actual control that is neither side's realistic maximum; this potential loss is offset — for both sides — by eliminating the risk of an even worse outcome.
Are there signs that Ukraine and the West would be willing to, however grudgingly, factually (but not politically or legally) accept a Russian occupation and enter cease-fire talks? The benefits of, say, accepting the current line of control would be to eliminate the risk of further Russian incursions. The downside is the loss of the occupied areas and that an illegal invasion is accepted as successful. If Ukraine is not willing to negotiate now: What are their exit strategies, given that re-conquering the occupied areas seems unrealistic?
Note: This war was full of surprises. I'd be happy about answers challenging my assumption that re-establishing territorial control is unlikely.
Addendum: Right at this hour a NYT opinion piece has been published lamenting the ill-defined Western war goals and the lack of diplomatic efforts to end the war which makes arguments close to mine.