Violent encounters between states and rebels and the international community's assumptions about how Africa's states should be governed underscore the last half-century of warfare on the African continent. The founding compact of the Organization of African Unity (OAU) in 1963 that forbade countries from conquering their neighbors' territories had a very real impact in nearly eliminating conventional wars between African states. Much of this had to do with the mutual recognition of vulnerabilities. But the wider global decision that international borders would be sacrosanct no matter how illogical or inconvenient they may appear has turned attempts at conquest such as Iraqi leader Saddam Hussein's bid in 1990 to annex Kuwait into futile projects that generate almost total condemnation by other states and in this case reversal by a military invasion. This compact has largely held in Africa, as it has in much of the rest of the world. The Tanzanian invasion of Uganda in 1978–79 forced from power Uganda's President Idi Amin after he had violated this compact with his occupation of a chunk of Tanzanian territory. Ethiopia's and Eritrea's war, which broke out in May 1998, was about the exact location of an international border, not its revision. The Ethiopian army's 2006–09 intervention in Somalia came at the invitation of the weak, UN-backed transitional government. Morocco's war to annex Western Sahara on Spain's withdrawal from its colony in 1976 really was an irredentist exception, although some argued that Morocco made no claim against the territory of an existing sovereign state.