The current war being carried out against America and modernity is dated by me to the murder of Attorney General Robert Kennedy in June 1968 by Sirhan Sirhan.
The war was operated in a terrorist mode with the bombing of a Marine barracks in 1983 and of the World Trade Center in 1993 and repeated by Al Qaeda in 2001. The terrorist component continues and gets more aggressive. The most prolonged intense terrorist battles were by Palestinian Muslims in 1987 lasting until 1993 and again in 2000.
The combined modes of terrorism and guerrilla converged in 2014 with the formation of the Islamic State army in Syria and Iraq. The terrorism continues in many parts of the world and guerrilla battles rage now from Libya to Nigeria.
So far, the American government and its allies have not recognized the War as a war. Thus, we must consider it as just beginning. Most wars have multiple components of terrorism, guerrilla operations and battle trained armies. This war is likely to operate on all three levels for quite some time.
How long this war will last is hard to predict. Religious wars have often lasted centuries. Wars against modernity (Confederacy, Hitler, Stalin, Palestinians, Mao and Ho Chi Minh ) have lasted decades.
We are now in year 48 of the Great Islamic War. I have no reason to believe it will be short because it is deeply embedded in a large religious population.