Courtesy of the Didact reposting, it's a message that has not lost its timeliness. namely, what one LTC Kratman has to say about pitiless war.
Here is what a decorated veteran of Operations Just Cause, Desert Storm, and Iraqi Freedom, LTC Tom Kratman (US Army - Ret) had to say in response to a rather pompous declaration by a quite gormless doofus who just happened to be Le President de France back in 2015 in the wake of the Bataclan Islamist attacks:
Let me tell you what a pitiless war would look like. Firstly, your armed forces would be culled of Moslems, with those in it interned. While this was going on, the police would have the DNA of the attackers analyzed. While the analysis was taking place the now culled armed forced, not least to include the Gendarmerie, would be surrounding the banlieus that contain the most Moslems. It would be announced that any Moslem found outside his or her home after dark, or more than 400 meters from it during the day, would be subject to summary execution. As wire was emplaced around one banlieu, thereby freeing up some troops, others would be encircled. Their orders would be to shoot anyone trying to leave though anyone would be allowed to enter. Food and water would be shut off. Then one by one you would go through the banliues, taking samples from everyone. Anyone whose DNA indicated they were related the attackers, male or female, old or newborn babe, would be killed on the spot. Then you would burn the mosques. You might potentially not kill the genetically implicated on the spot, but herd them into the mosques before you burn them. If you could identify one banlieu, or perhaps two or three, from which the bulk of the attackers originated or which provided the most non-combatant support, you would turn it into a modern Lidice or Ourador sur Glane.
Keep in mind that for all intents and purposes, A Desert Called Peace, his colonized "almost like earth" series is a thinly skinned how-to on how ruthlessly the good LTC thought the war on terror should have been fought. The one-sentence summary being "kick their faces in, show them how ruthless you are, showing them you really, really don't want them getting your attention again."
It's also worth noting that while our protagonist did go to settle issues in the not-middle-east, he didn't stay there.