Would you believe me if I claimed that Daesh were not real in the main. They are not Islamic because they put their own desires first. They are mostly internet warriors. If the US (and recently Jordan) rains down fire and horror through bombs from the sky, ISIL does so through astounding staging of online events. Around them is nothing but destruction so they aim to win through more destruction...of viewers' sensibilities. They win the war (which has no expected aim) because Coalition bombs destroy and burn but without witnesses. (Has anyone seen their Syrian capital today on TV?) Their staged events also make everyone wonder what to do against them. The real destruction of the Coalition will not work (although whether killing the leaders might work is a solid question). They also cannot be matched in online warfare (should Jordan draw and quarter a captive online?).
Suggestion: Kill them with kindness. They expect bombs, lies, and misrepresentations. Pure kindness (real and virtual) is not expected. Use the same amount of funding now deployed to destroy their region to instead 'kind their region.' It is the only way to win.