Always strive to learn something useful. --Sophocles

Given America's position in the world, it's scarcely to our advantage to encourage non-state groups to engage in asymmetrical warfare, even if it *is* against our enemies. It will come back to bite us in the ass, even if we do gain some temporary advantage from it. The safest long-term course would be to help Poroschenko hunt them down, and set the example that when you do this sort of thing, both sides will team up against you.