We are a violent species. We have been fighting wars since before recorded history. The first wars were fought over territory,or prehaps for possession of precious natural rescources such as the user of a stream. In the past several thousand years, inumerable wars have been fought for the acquisition of political or relgious supremacy.
I am totally against war, and would like to see it banished from human affairs. It is my belief, however, that fighting a war is justified in special circumstances, such as when freedom or survival is at stake. The American Revolution,for example was justifiable. The colonists rebelled in order to gain the right to worship as they pleased and to gain freedom from taxation without representation. World War II was a just war, with the Allies fighting to stop Hitler from achieving world domination. However wars that are fought in the name of religious freedom can become unjustified, and lead to persecution and massacres. Starting the war in what formerly Yugoslavia wasn't justified. Ethnic prejudice is not the same as fighting for self-rule or survival.
There should be a world court to peacefully mediate disputes between countries or groups of people. The United Nations has tried to fill this role for 50 years, but doesn't have the power to enforce its decisions. If we had a global organization powerful enough to do so, we might have a world with only justified wars or, better still, no wars at all.