Nationalism, which many in the power-mad set refer to as patriotism, is inherently uncivilized. The history of civilization is one of smaller groups combining with larger groups for the purpose of public safety. Tribe to village to city to region to state to country. Here is the US, the Constitution requires the states to behave in a civilized manner with each other. We can assume that if there wasn't a federal government to settle the differences, any given state would go to war with any other as soon as they couldn't resolve their differences themselves. But they end up with a ruling from Congress or the Supreme Court and they have to accept it, whether they like it or not.
Until we have a world government that can force the compliance of all nations we will have war. Wouldn't it be nice if Israel and Palestine had to take their differences to the world court and then had to just accept the ruling that came down? Everyone could just get on with their lives even if they disagreed with the decision. People who take up arms because they disagree with a ruling would create a police situation instead of a war, mostly because the entire rest of the world would back the court's decision. It would be sort of like if the city of Detroit decided to declare war on Ann Arbor. They wouldn't get very far. They know that the United States army would land on them so fast and so hard that they don't even think about going to war with each other. They sue each other and accept the final verdict. Much less loss of life.
This would, of course, require that the United States and every other country give up their sovereignty. Until we find a way to do that we will be uncivilized.