CHARLESTON, W.Va. -- "The single event that has defined the 21st century" -- that's how one scholar describes the historic terror attack that killed 3,000 Americans on Sept. 11, 2001.
Although fanatical extremists previously inflicted murder in some remote places, the stunning, sickening, 9/11 suicide assault, especially in New York City, forced the world to see jihadism as a global menace.
Ever since, zealots willing to die to commit mass slaughter have become the foremost cause of bloodshed -- supplanting the Cold War as the chief source of strife.
"Since that attack, there have been bombings in Indonesia, Kenya, Spain, Britain, Egypt, Uganda, India, Nigeria and many other countries, while other nations such as Afghanistan and Iraq have lost tens of thousands of lives as part of the American reaction to the conflict," researcher Murithi Mutiga wrote. "In Africa, al-Qaida has established a foothold in Somalia, taken over large swaths of territory in the desert states of Mali and Niger and struck ties with militants that have destabilized northern Nigeria."
With 9/11, the world fully entered the era of self-chosen "martyrs" -- volunteer killers with so little to lose here on Earth, who think that their massacres serve a divine purpose. The 19 young men who attacked America in 2001 left behind handwritten testimony saying they expected to be rewarded by "the women of paradise."
Since then, suicide attacks have formed almost a worldwide pattern -- so routine that they barely make international news. That's the situation today.
As America marks the 12th anniversary of the tragic landmark, more than a decade into the "new" style of conflict, U.S. citizens, their representatives and their allies struggle with what to do about Syria. What should the rest of the world do in response to reports that Syrian President Bashar Assad used chemical weapons on his own citizens?
Whose job is it to respond to that deadly injustice? Who polices the world?
There is nothing new about that question. People debated it a century ago leading up to World War I. They debated it before World War II, and after that war created the United Nations in part to deal with exactly this kind of problem.
On this tragic anniversary of the defining event that differentiates the 21st century from the past, it turns out not so much has changed after all. The questions and problems of the 20th century are still very much with the world.