However, I think their calculation here speaks to the difficulty of the current situation.
Putting aside the morality, sovereign integrity, and such: the situation appears to be entering/in a stalemate. The Ukrainian forces have done well to proactively take and hold Russian territory, and have held the line pretty well. However, there does not seem to be a play here that will conclusively end Russian occupation presently. The best case seems to be waiting out the supply of Russian troops, but the Ukrainian army doesn't have an endless supply of volunteers in this regard (I've worked with a few who have).
So the question has to be asked: how does this end decisively if neither side can win outright? And how much support is required to maintain the status quo?
I hate to say it, but I think they will likely have to lose territory. I think they could argue for greater security architecture (i.e. part of NATO but no nukes) to prevent repeat. But otherwise I can appreciate why the current administration is where its at.
Its a sorry situation all around.