Finance and funding is where its hits the hardest for these militias. Without enough funding the Islamic State will become a lot weaker and eventually cease to exist. The Islamic State has been selling oil to a web of buyers which has allowed for the longevity of the group's survival. When these transactions stop, the funding required for keeping the petroleum technicians and engineers will disappear, and the decline in production will eventually have a huge effect on the terrorist group's operations.
[P1] Oil trade with IS provides the terrorist group with funding. [P2] Cuts in funding with limit terrorist operations.