A polity which is the only one representing that species.
I mean, that's not possible, because no species is completely unified. There are multiple canonical examples of independent human polities that aren't part of the UFP or U.E. -- the entire Human species is not part of U.E. We also know canonically from DIS S3 that Vulcans and Romulans are the same species, so obviously the Confederacy of Vulcan is not a polity that represents the entire Vulcan species.
It's also impossible because migration within the Federation exists. We know canonically that there are Humans who live on Vulcan, and Orions that live on Earth, etc. Are you contending that Humans who have lived on Vulcan for four generations should have to be considered as United Earth citizens, get to vote in United Earth elections, receive no representation in the Confederacy of Vulcan's government, and be represented in the Federation Council by the Councillor for United Earth instead of the Councillor for the Confederacy of Vulcan?
The issue is one of maturity not geography. Whether the "Australians" are on a continent on Earth or on the next planet over, the issue is can the humans play nice with each other?
I mean, sure, but that's still a question of political unity under a single polity, not a question of biology or geography.
We’ve seen humans that are no longer or that perhaps have never been under the auspices of the Federation, but we've never seen a Federation memberworld separate from other humans.
I'm not sure what "Federation Memberworld separate from other humans" means. Do you mean a Federation Member polity that is majority-Human and is not part of United Earth?
Flooding the polls with billions of cloned beings programmed with the memories and minds of existing Arcturians is gaming the system and is in no way having free and democratic elections.
I mean, if the Arcturians actually had that capacity, then Starfleet would not have had a manpower shortage during the Dominion War, now would it? So I doubt that bit of behind the scenes apocrypha from TMP is "real" within the canonical Star Trek Universe.
If it
were real though, I still don't think sentient beings should be discriminated against as you suggest. I also don't think those clones would be as uniform in their thinking as you describe. Sentient beings have a way of refusing to fit into narrow parameters.
It would invite every memberworld to do the same, or more realistically to vote to expel the Arcturians from the Federation, if not to outright declare war on them depending on when the election tampering first began and what effect it's had.
"Declare war?" Well that escalated quickly!
This is the sort of thing that would be decided on before the Council votes on whether to accept Arcturus as a Member. It would never escalate to such a dramatic level in the first place.
But again, I doubt this is even an issue because nothing about these supposed Arcturian abilities makes sense in the context of other ST installments.
They're not accepted in Starfleet; we don't know if they'd be accepted as members.
"Ghosts of Illyria" and "Ad Astra Per Aspera" established very explicitly that a polity where genetic augmentation is practiced must ban such practices before it can be accepted as a Federation Member.
Plus, it may depend on the kind of genetic-engineering. SNW did show us a Denobulan redshirt. Was he not genetically-engineered at all or not beyond a certain point that would give him an unfair advantage, or is there an accommodation made for Denobulans–maybe a limited number of slots for them or above a certain rank or within certain divisions.
If Denobula is not a Federation Member State, then presumably a Denobulan citizen needs to meet the same legal requireents any foreign citizen must meet to become a Starfleet officer, as we saw with Nog in DS9. Since "Dr. Bashir, I Presume?" established that people who have been genetically augmented cannot be Starfleet officers, presumably this applies to foreign applicants.
Vulcan vetoing its membership. Andor could legally free dozens of colony worlds to have a huge advantage over solitary Vulcan, and everyone else.
You're presupposing a level of hostility between Federation Members that seems implausible.
You're also overlooking that, again, being the same species does not mean your interests are the same. We are talking about polities with hundreds of millions, if not billions, of people -- if a former colony world is petitioning for separate Membership as a "plant" to give those two Members votes they can use against other members, the rest of the Federation will know and veto the Membership application because you're talking about too many people to keep something like that a secret.
That does not mean there can't be real, valid reasons why the interests of one world might diverge enough from the interests of its "mother planet" as to warrant separate membership. No one accuses Aotearoa New Zealand of holding separate membership in the U.N. just to give the U.K. another vote in the General Assembly, after all. Maybe there's a Vulcan colony world whose population have rejected the teachings of Surak and become v'tosh k'tur but want to stay in the Federation -- seems reasonable that maybe they would want to become a separate Federation Member in their own right.
Not everyone of a species needs to have the same beliefs and interests, but trends tend to arise out of similar populations of beings.
Ah, but why do you assume being the same species means they're going to be a "similar population" in any meaningful sense? We all know how different and often conflicting different nations of Humans can be in real life, and we're all one species!
Again, it's why we have a Senate as well as a House.
No, we have a Senate because the Framers chose to to protect slavery and class inequality from abolitionist and wealth redistributionist movements.
Only if the Federation is more like the United States (or Canada) and less like the United Nations.
Which we already know it to be. The United Nations does not have a standing military; the Federation does, in the form of Starfleet. The U.N. does not have or confer citizeship; the Federation does. The U.N. does not possess territory over which it is sovereign; the Federation does. The U.N. Secretary-General cannot declare a State of Emergency and put New York under martial law; the Federation President can declare a State of Emergency and put Earth under martial law. The U.N. cannot per se make binding law; the Federation Council can.
There are some ways in which the UFP is like the U.N., mostly in the sense that Members are clearly very autonomous and likely conduct relations with one-another through the Federation. But in most ways, the Federation behaves more like a sovereign state than not.
I think it's already established that the Federation isn't very much like the USA either. It apparently allows members to withdraw (and be readmitted later on).
But a sovereign state like the U.S. or Canada has the right to allow its constituent polities to secede if it wants to. The United Kingdom allowed Scotland to hold a referendum on independence just 10 years ago, for instance.
Would the USA allow say, California, to secede if it turned out 95% of the Californians were in favor of that?
I mean,
95% of a state's population wanting independence is a level of political consensus that has never existed in the real world, so it's impossible to answer. But the U.S. has every legal right to allow California to secede if it wishes. So there's no reason the Federation can't both be a sovereign state
and allow a legal process for its Members to secede.