While nobody is likely to defend Ukraine, arguably it is entitled to consider itself free of any obligations under the non-proliferation regime. It certainly has the expertise to re-establish nuclear capacity and it should not be hindered by the powers that have failed as guarantors.
Ukraine getting nukes is a great idea actually, since contrary to alarmists nukes prevent war. The reason the US and the Soviets were able to avoid war was the possibility of mutual destruction. A nuclear Ukraine could prevent a further escalation.
