It was and still is a Sovereign State. Except now it is a failed State thanks to Western invasion. I don't know where you get your definition of "Sovereign State" from but in the dictionary it has a clear definition: "a state with a defined territory that administers its own government and is not subject to or dependent on another power."
Merriam Webster: "Nations and states are also sometimes described as "sovereign." This means that they have power over themselves; their government is under their own control, rather than under the control of an outside authority".
It doesn't talk about "Democracy" anywhere. Nor does it state that the State is Sovereign only when it is by the people.
> legitimate sovereign dictatorship, the notion of national sovereignty doesn't exist in the context of slavery: the people in question were not sovereign.
Bullshit.
> Any free foreign nations had a moral right to invade the US south before the US Civil War and attempt to free the slaves
Bullshit again.
> Any free foreign nations had a moral right (not a moral requirement) to invade Libya in an attempt to free its people from Gaddafi's dictatorship.
More bullshit.
"Sovereign State" has nothing to do with political nature/structure of the State: it can be a Democracy, Dictatorship, Religious State (like Vatican or Islamic countries) or anything it wishes to be. You, me or anyone else in the World have no moral standing to bomb it to oblivion and destroy it. Period. It is for the people to decide. If they want to overthrow the Dictatorship it is their Right to do it. They can do it. There was already a Civil War in Libya to oust Gaddafi. The people would have decided to bring down Gaddafi on their own. There was no need for Western invasion of Libya. The Western invasion was for nefarious purposes. But I'll be digressing.
Also, if Libya wasn't a "Sovereign State" it wouldn't even be a member of the United Nations.
Do you mean to say you have every right to invade most Islamic Nations because they aren't democracies? What about the Vatican? You feel you should invade it and "free" the people because it is not a Democracy? It is a Theocracy and a Dictatorship too.
> Ukraine was a sovereign state and a burgeoning liberal democracy, which is why Russia had to try to destroy it.
Russia is wrong too. Not going to defend Russia here. No country has any moral standing to invade another country unless the Government in power, in that country, asks for help or the country attacked your country.
Anyways, even if I go by your definition of it being a "moral right" to invade a Dictatorship and "free the slaves", even in that mission the West failed miserably. The West replaced Dictator Gaddafi in Libya with Islamic Terror groups/warlords + Slave markets. The West replaced Dictator Saddam Hussein in Iraq with ISIS + Slave markets. Demolished all Civilization and turned them into literal ghost towns. The West invaded Afghanistan to catch Osama Bin Laden and get rid of Taliban, demolished everything, rebuilt everything, and when we were all going to exclaim that finally one US intervention led to peaceful Afghanistan with Democracy, the US left, without cleaning out the Taliban, with Taliban taking over the Country + 85 billion dollars worth of advanced weapon systems.
So even by your own definition of establishing a "Sovereign Nation", the West failed in achieving its objectives.