The Nazis were very effective at countering resistance. They would fill every mosque around Paris for twenty miles with Muslims and burn them alive. They would track down and in the early hours drag away every so called militant muslim and disappear him after excruciating torture. They would employ armies of informants. This it seems is the game ISIS is now playing. No barbarity is excluded from their strategy of terror.

A theatre nuclear weapon on the ISIS HQ would be a good first step.

"The Davy Crockett recoilless spigot gun was developed in the late 1950s for use against Soviet armor and troops if war broke out in Europe. Davy Crockett Sections were assigned to USAREUR (United States Army Europe) armor and mechanized and non-mechanized infantry battalions. During alerts to the Inner German border in the Fulda Gap the Davy Crocketts accompanied their battalions. All V Corps (including 3rd Armored Division) combat maneuver battalions had preassigned positions in the Fulda Gap. These were known as GDP (General Defense Plan) positions. The Davy Crockett sections were included in these defensive deployment plans. In addition to the Davy Crocketts (e.g., assigned to the 3rd Armored Division), V Corps had nuclear artillery rounds and Atomic Demolition Mines, and these were also targeted on the Fulda Gap

Both recoilless guns proved to have poor accuracy in testing, so the shell's greatest effect would have been its extreme radiation hazard. The M-388 would produce an almost instantly lethal radiation dosage (in excess of 10,000 rem, 100 Sv) within 500 feet (150 m), and a probably fatal dose (around 600 rem, 6 Sv) within a quarter mile (400 m).[3] The weapon did not have an abort function; if fired, the warhead would explode."

wikipedia