Serbia can really do nothing - Ok recall embassy staff and set fire to things. Don't think Serbs in Kosavo will be hamed but if they do something stupid think they will have to expect issues.

If this happens I am sure there will be issues in the whole of the Balkans.

Will Russia get involved - don't think so as apart from being Orthodox would they wish to take on NATO. Most likely they will recognise breakaway states in Georgia at most.

Believe lots of words currently which with luck will die down and most Serbs are bitter at, but resigned to the loss of Kosovo, and tired of long years of conflict with neighboring states.