The annexation of Kuwait by Iraq, the annexation of the Golan Heights by Israel, and the annexation of Crimea by Russia are examples of recent territorial annexations that have been rejected by the international community. Under what circumstances has the international community historically accepted or rejected territorial annexations, and what were the reasons?
Have the reasons remained consistent throughout history, or have they evolved after, say, the Peace of Westphalia and other international territorial agreements? How has "rejection" been handled (i.e. Iraq was invaded by the West but Israel and Russia were not), and has that been consistent? What generally has to happen for an annexation to be accepted? Has annexation against the will of the people living in the disputed territory ever been historically accepted, and what percentage of the population accepting the annexation is generally regarded as being enough? How can such will even be expressed or measured?