In an episode of The West Wing called “Isaac and Ishmael,” White House Deputy Chief of Staff Josh Lyman scribbles this SAT stylized question—the room is full of high schoolers—on a dry erase board: "Islamic extremist is to Islam as _______ is to Christianity."

You may recognize the proper noun that fills the blank, the Klu Klux Klan, for burning wooden crosses, a symbol of Christian faith. Lyman illustrates a valid truth: Muslims aren't terrorists. Brown skinned people with a lineage that ties back to the Middle East aren't terrorists. But, what exactly is terrorism? The Oxford English Dictionary defines it as so:

Terrorism: A system of terror. 1. Government by intimidation as directed and carried out by the party in power in France during the revolution of 1789-94; the system of `Terror'. 2. gen. A policy intended to strike with terror those against whom it is adopted; the employment of methods of intimidation; the fact of terrorizing or condition of being terrorized.

To wit: Terrorists are people of any creed or code on the far left or right of a political or religious spectrum who act on their extremist views. Al-Qaeda and the Klan and the Nazis are one in the same. Terrorism is about power and politics. In order to carry out an ideology, terrorists often commit violent acts. And though the definition of terrorism from the famously erudite OED may be changing (see: recent developments in cyber-terrorism), violence remains the most prominent word. With that in mind, here is a list of the Most Violent Terrorist Groups in the World Right Now.