The Lawfare Blog has proposed its own similar lexicon of violence, and it is even less useful. It has two major flaws, which I will explain once I give you the lexicon.
Violent Extremist Organization: An organization that takes action to further a Violent Extremist Ideology.There are two big issues here, as I mentioned.
Violent Extremist: An individual who take actions to further a Violent Extremist Ideology.
Resident Violent Extremist: A Violent Extremist who takes actions to further a Violent Extremist Ideology in the same State in which they are considered a national under the operation of its law.
Non-Resident Violent Extremist: A Violent Extremist who takes actions to further a Violent Extremist Ideology in a different State than that in which they are considered a national under the operation of its law.
Supported Violent Extremist: A Violent Extremist who receives support for their actions from another Violent Extremist or a Violent Extremist Organization.
Unsupported Violent Extremist: A Violent Extremist who does not receive support for their actions from another Violent Extremist or a Violent Extremist Organization.
Inspired Action: When a Violent Extremist takes action that is inspired by a Violent Extremist Ideology.
Directed Action: When a Violent Extremist takes action based upon direction they received from another Violent Extremist or a Violent Extremist Organization.
Spontaneous Action: When an individual with no known previous plausible ties to a Violent Extremist Ideology, Violent Extremists, or a Violent Extremist Organization, suddenly takes action, with little planning or preparation, to further a Violent Extremist Ideology.
Opportunistic Claim: When an individual with no known previous plausible ties to a Violent Extremist Ideology, Violent Extremists, or a Violent Extremist Organization engages in violence, and a Violent Extremist or Violent Extremist Organization claims responsibility without providing proof that they inspired or directed the action.
1) All of this is ultimately rooted on the definition of "Violent Extremist Ideology," which is unspecified. Thus, the whole thing is groundless. Specifying exactly what a Violent Extremist Ideology is -- so that it captures all and only the right kind of actors, leaving legitimate political actors alone -- is the real work to be done, and it's untouched.
2) This approach elides essential differences. By essential differences I mean things that make the other things necessary. The first lexicon accurately captured that a commitment to jihad was what was making all the violence necessary. The right wing groups are doing whatever they're doing for entirely different reasons. Violent Communist groups, like the Maoists in the Philippines, are necessarily committed to violence out of a different essential understanding of the world and their place in it. Since ultimately you have to get at the motivations of violent groups in order to make the violence go away, collapsing these essential distinctions is a terrible idea.
The motivation for all of this is to try to treat different kinds of radical groups "equally," I suppose. Yet equality isn't what we're interested in here: we don't have to be afraid of being unjust to people who run over children with big trucks. We need to retain an understanding of just what is moving them to do all these things, because it is that motivating force that we ultimately have to deal with.