As Wolff and Bieber note, if we boil things down and simplify, there are really three possible outcomes: the ICJ says Kosovo's independence is legal; that it is illegal; or that the situation is a bit mixed and no general principles can be applied/developed.
Under Scenario 1, the ICJ says that Kosovo did not break international law:
- Those strongly supporting Kosovo will go along their way, patting themselves on the back but also note that the decision only applies to Kosovo and does not create a general right for all secessionists to run with the decision.
- Those strongly opposed will question the legitimacy of the decision, blaming undue American influence, and ignore the decision. And say that there is no general right to secession.
- Quebec sovereigntists will take a positive decision to justify yet another referendum because Quebec is just like Kosovo.
- Canadian federalists will assert that Kosovo and Quebec are distinct, with the former escaping from significant oppression and the latter having both significant autonomy and power within the federal system.
- Other separatists around the world will not become suddenly inflamed because they know that their major opponent, their host state, will not suddenly swoon and obey the ICJ ruling.
Under Scenario 2, the ICJ waffles and does not provide a clear decision with clear ramifications for the rest of the world.
- Those strongly supporting Kosovo will say that their support is justified, patting themselves on the back but also note that the decision only applies to Kosovo and does not create a general right for all secessionists to run with the decision.
- Those strongly opposed will say that their opposition is justified, blaming undue American influence. And say that there is no general right to secession.
- Quebec sovereigntists will take a mixed decision to justify yet another referendum because Quebec is just like Kosovo.
- Canadian federalists will argue that Kosovo and Quebec are different.
- Other separatists around the world will not become suddenly inflamed.
- Those strongly supporting Kosovo will ignore the decision, saying that they had no alternatives and that it cannot be undone.
- Those strongly opposed will feel better about their opposition but will not supporting secessionists they like (that would be Russia and the various quasi-states on its periphery).
- Quebec sovereigntists will say that the decision does not have implications for another referendum because Quebec is different.
- Canadian federalists will be confused, as they support Kosovo independence but oppose Quebec independence.
- Other separatists around the world will not de-escalate because their efforts are not legitimate by the court's eyes--they have been marching, voicing, fighting for years without international legal cover so not much will change here.
What would I want to have happen here? Well, if the international community really supports the responsibility to protect and all that comes with it, it would make sense for the ICJ to allow for a remedial right to secession (as the normative literature on secession call it)--those who face significant repression/oppression should be allowed to determine their future and secede. Those who are not oppressed (that would be you, Quebec) would not have a right to secede, as granted by the international community. If host states, such as Canada, let their wayward provinces go, that is something else. But again, I am skeptical that norms will stop committed actors from doing what they want, at least in the short term and especially when domestic political incentives push in a particular direction (see Ties That Divide).
* the phrase Unilateral Declaration of Independence was largely foreign to me until I moved to Quebec, where there is much consideration of UDI's. For me, I always thought any Declaration of Independence was unilateral since one would not need to declare it so much if a group (secessionist or anti-colonialist) and its host state agreed to part ways.