As Kosova became the Europe's newest state on Sunday – supported by the United States and most of Europe – it did so without United Nations Security Council approval, the guarantor of legality among nations. Russia calls Kosova independence illegal, a "Pandora's Box," in the words of Foreign Minister Sergei Lavrov. Serbia, a UN member, says Kosova succession "violates its ancient, sovereign territory". Cyprus and Romania cite a "dangerous precedent in allowing minority groups to split willy-nilly".

Even some diplomats supporting Kosova say that on legal grounds alone, the arguments – Serbian sovereignty vs. ethnic Albanian self-determination – are inconclusive. They say Kosova is a political not a legal problem – one clouded by nine years of world attention on Iraq, Guantánamo, and an erosion of America's high ground after the Berlin Wall fell.

"I worry that we've forgotten how we got here [to Kosova independence]," says William Walker, head of the Organization for Security and Cooperation in Europe mission in 1999 to verify that Serbia was not using excessive force in Kosova. "I visited the site of a mass execution in Racak the day after it happened, before the Serbs could clean up the story. Such events were taking place all over Kosova, as they did in Bosnia and Croatia. This led to NATO intervention."

Indeed, supporters say the Kosova case is unique: The dissolution of Yugoslavia, the ethnic cleansing of non-Serbs in the Balkans conducted by Serbian state actors, the second-class status of the majority Albanians and their refusal to ever accept Belgrade as a capital – creates an exceptional confluence of historical, moral, and practical claims.

A central legal issue bears on the breakup of Yugoslavia, and Kosova's former status in it. Kosova was not a republic. But it had a special status. It not only had veto rights and a president in Yugoslavia's rotating presidency, it had representation in all aspects of federal Yugoslavia – parliament, courts, civil administration. Analysts say Kosova benefited from the balancing of its status among the other five republics of Yugoslavia – all of which now exist as separate states. Serbia can't offer Kosova what Yugoslavia offered it, they say.

"You cannot return Kosova to anything like the status it enjoyed under Yugoslavia," says Albert Rohan, former Austrian foreign secretary who worked with Finnish diplomat Martti Ahtisaari on a UN plan for Kosova. "It is not that the other republics like Slovenia separated, it is that Yugoslavia dissolved."

Then there is the issue of minority rights. Under Serbia, Albanians were treated as a minority, even though they are the third largest ethnic group in the Balkans. Their language, rights, and status in Serbia was not an equal partnership. Serbian intellectual Dobrica Cosic in the 1970s and 1980s went so far as to argue in a famous memorandum from the Serbian Academy of Sciences that Albanians never really lived in Kosova prior to the modern period. Serbian dictator Slobodan Milosevic turned the memorandum into a Greater Serbia policy of denigration and humiliation of Albanians, essentially forcing them to create a parallel structure of schools and government. (Oxford scholar Noel Malcolm argues that "the Albanians are one of the oldest established populations in Europe.")

Even today, Serbian Prime Minister Vojislav Kostunica refuses to accept the Kosova Albanians either as full citizens of Serbia or as citizens of an independent state," argues James Hooper of the Public International Law and Policy Group in Washington.

For Skender Hyseni, spokesman of Pristina's "unity team" of negotiators, the argument for independence was practical. "Milosevic carefully planned ethnic cleansing of the Albanian people and used state institutions, police, and paramilitary structure to implement this policy," he says. One million people were driven out of Kosova in the days around NATO's bombing, he says. "It was a gambit by Serbia of a nonconsensual breakup or collapse, to rid Kosova of Albanians. To now say we can't remember this is impractical as a political reality."

Kostunica recently called for a pre-annulment of any independence deal by Serbia's parliament, and argued against an agreement to start talks to become a member of Europe, saying "There would be no greater humiliation than for Serbia itself, in any way, to sign or give its indirect consent to the existence of a puppet state on its own territory."

Prior to the Ahtisaari plan that will give Serbs enhanced minority rights in Kosova, diplomats confronted the question of independence. It was decided Kosova could not be "half-independent," says one insider. "We opted for independence for two reasons: One, you can't go back to 1989 as if nothing happened. Two, you can't implement something less than independence, that 95 percent of the people won't go along with."