There are significant differences between the Islamic State and the white nationalist terrorists who have been ramping up attacks in the U.S., but "the parallels are stunning," terrorism expert Will McCants tells The New York Times. In fact, writes Max Fisher at the Times, "white nationalist terrorism is following a progression eerily similar to that of jihadism under the leadership of the Islamic State, in ways that do much to explain why the attacks have suddenly grown so frequent and deadly."

The parallels include an apocalyptic ideology that promotes a world-consuming civilizational conflict — for ISIS, Muslims versus the West; for white nationalists, nonwhites versus whites — showy and indiscriminate murders recorded and shared over social media, purportedly to hasten this global battle as well as recruit and radicalize new adherents, and new forms of communication that allow such violent ideologies to spread virulently, typically among young male loners.

"I think a lot of people working on online extremism saw this coming," J.M. Berger, author of the book Extremism, told the Times. And there are good reasons to be very worried that it came to fruition, Fisher explains:

The feedback loop of radicalization and violence, once triggered, can take on a terrible momentum all its own, with each attack boosting the online radicalization and doomsday ideology that, in turn, drive more attacks. The lessons are concerning. It is nearly impossible to eradicate a movement animated by ideas and decentralized social networks. Nor is it easy to prevent attacks when the perpetrators' ideology makes nearly any target as good as the next, and requires little more training or guidance than opening a web forum. [Max Fisher, The New York Times]

Read more about how the U.S. invasion of Iraq helped foster this new form of nihilistic terrorism and the nearly word-for-word similarities between the ISIS and white nationalist manifestoes at The New York Times. Peter Weber