I'm not sure I exactly follow, but I think there's a definitional issue here that's maybe caused some confusion. Not sure though. But here I go anyway: Ukraine, and anyone else, obviously could join NATO. But they don't have a sovereign right to membership by nature of being a sovereign state. It's essentially a club and the club decides who gets in. However, Ukraine obviously has the right to request membership (in fact, they did long ago). And the people of Ukraine have the right to push their government to join.
Even the UN gets to decide who it lets in, and geopolitics has left some states out (Taiwan and Palestine for example). Because there's no sovereign right to be a member of the UN, it turns out.
I'm not sure I exactly follow, but I think there's a definitional issue here that's maybe caused some confusion. Not sure though. But here I go anyway: Ukraine, and anyone else, obviously could join NATO. But they don't have a sovereign right to membership by nature of being a sovereign state. It's essentially a club and the club decides who gets in. However, Ukraine obviously has the right to request membership (in fact, they did long ago). And the people of Ukraine have the right to push their government to join.
Even the UN gets to decide who it lets in, and geopolitics has left some states out (Taiwan and Palestine for example). Because there's no sovereign right to be a member of the UN, it turns out.