The saying is that history repeats; yet it cannot repeat exactly, it repeats more like variations on a theme. Here’s a repeating theme: Some powerful SOB(s) hires or enthralls a bunch of scum, dresses them in black (like death) and sends them out to commit atrocities on an unsuspecting populace.
Ivan the IV, czar of Russia had lots of good reasons to become a vicious, deranged killer, starting with the murders of most of his family as a small child and abuse by their murderers for years. This ended when he was thirteen and loosed his dogs to tear one of them apart in public.
Then he grew up and got worse. He hired about 6,000 lowlifes, dressed them in black and turned them loose on his suspected enemies. These Oprichnicki rode black horses and carried a broom and a dog’s skull as symbols of “cleaning up” and guarding their master. They raped, tortured and terrorized the countryside, and did so in the cruelest ways they could dream up. In one town, they killed 60,000 people.
The Ringwraiths, or Nazgul, in Lord of the Rings, also dressed in black, rode black horses and obeyed the evil Sauron. Compared to the Oprichnicki, they are almost sympathetic characters, creepy as they are, because they no longer have free will, having sold their souls to the One Ring, i.e. Powerlust.
ISIS also obeys foreign masters, dresses in black, and commits the most hideous atrocities they can dream up. But this is 2014, so they ride in Toyotas and post their crimes on Youtube. That they intend to psychologically terrorize people is obvious.
Another thing they have in common is a spiritual element: the Oprichnicki impersonated monks, the Nazgul look like monks and ISIS claims to represent Islam. One Sunni cleric called them “dogs from hell.”
If history repeats, then ISIS will end when their sponsors stop supporting them.