the reason that the americans have been apprehensive about sharing military technology with the ukrainians is the realization that it would end up sold to the russians by corrupt actors within or russian infiltration of the ukrainian state. everything else aside, ukraine cannot be admitted to nato because it would be a security and intelligence breach and would create a backdoor for russian infiltration into nato itself.
it is likely that ukraine will be forcefully told it cannot join nato and the pentagon was just stringing them along the whole time as an excuse to inflict damage on russian defense capacities. nato doesn't give the slightest fuck about ukraine, ukrainian infrastructure or ukrainian casualties in the war. most recently, the americans have been asking ukraine to lower the age of conscription, which is enforced with extreme violence in ukraine by armed thugs in a stazi-like secret police that kidnap young people at gunpoint and send them off to war. the americans are increasingly and aggressively encouraging the ukrainian government to round up ever younger children to march them off to die, to kill some statistically greater percentage of russian conscripts and inflict some marginally greater level of damage on russian defensive abilities, which is reminiscent of what happened at the end stages of nazism in germany, where they started rounding up little kids and handing them machine guns and sending them after soviet tanks, to get entirely obliterated. does that sound like they care about ukraine to you?
a component of the ukrainian state may actually retaliate to that news by realigning with the russians and, if they do, it will likely get messy, but will demonstrate why they cannot be integrated into the west.
cutting them off will expose the depravity of the american policy, but that is already clear, and if trump is the fall guy he won't give a fuck. it is the correct thing to do to minimize threats of nuclear war and reestablish ukraine as a buffer state that can allow for some concept of tentative and uneasy peace.
the russians need something to exist between them and the nuclear arsenal in germany. that's not negotiable and trying to take that away was a mistake that led to the situation on the ground. they would rather it is poland, but ukraine will have to do for now and the ukrainians will need to accept their fate as what they are, which is a buffer state. that's too bad for ukraine. let them cry in their borscht, and sing their sad songs, and write their existentialist books and work together in communes to cope on the ground; they cannot transcend their condition, and must be told to suffer through it for the good of the rest of the world.