Today’s Islamic terrorist organizations are the modern army of Islam. These groups and many individuals who support them believe in installing Islamic law by force. This ‘army’ is an irregular force, which is what armies were prior to the rise of the professional army. The concept of the nation-state evolved at the same time as the professional army, which was well after Islam had been founded. The Islamic army has not been able to modernize well, a symptom seen in other aspects of Islamic governance as well.)
The armies of the crusades were the Christian army. They were not professional warriors. (Although the knights can be considered to be) Religions fielding armies was common during and prior to the Middle Ages. The rise of the nation-state and professional armies put an end to this. (Exception: Islam) Islam has been attempting to go through this process since the fall of the Ottoman Empire. Nationalism is weak at least in part because Islamic nationalism was far more entrenched and more important culturally. This is where the Islamic army obtains its generals and soldiers. It will require warfare to rid the world of this Islamic nationalism. It is like defending your country. If this is not a solid cause of war, I do not know what is. Like so many good Southerners in the U.S. Civil War and the good Germans and Japanese in World War II. And this is a BIG war.
Repeated suicide attack has only one other occurrence throughout history. As survival is the most basic instinct in living things, overcoming it on a scale as these two requires cultural upbringing that must share some characteristics. As the case against Japan in 1945, this will not be ended through peaceful means. It will require violence on the cultural level, one, which historically has been a driving force behind many of the worst of wars. The world has not had a World War since 1945. I am not certain that we are due, but this war of Islam against the United States will not end until either we become Muslim, or the Islamic world ignores most of what is written in the Koran. Either way, a massive war can be the only way to achieve this decisive result. I see only see one way out of a war involving WMD. Take out the governments of Syria and Iran. See what it shakes loose. ALL governments who support the Islamic armies are to be taken down. The other, far more likely event is the use of WMD by the Islamic army that triggers the main conflict.
Either way, this will require a war to resolve. And these issues are of the type that caused the U.S. Civil War. Good people on both sides. Enough evil on one side to require that they lose. I see no way out without waging organized warfare against Islamic nationalism.