what starts a war is different from what causes it.
Just as Herodotus is the father of history, Thucydides is the father of realism. To understand the geopolitical conflict zones of the 21st century, you must begin with the ancient Greeks. Among the many important lessons Thucydides teaches in his History of the Peloponnesian War is that what starts a war is different from what causes it.
Read more: The Origin of Wars | Stratfor