The only ideology that needs to defeated is that of USA exceptionalism with its incessant destructive meddling in the name of "democracy", or petroleum. Since 1945, every major world conflict has either been started or exacerbated by the USA. ISIS is/was a product of despair. People tire of having their homes burned and their children massacred, of having the land where they and their forebears have lived for millennia expropriated and given to foreigners, of having roving bands of bandits tearing down whatever pathetic society the locals manage to erect. Whenever a bit of stability appears to be germinating, you can can bet your ass that the USA will be there handing out M16s the way GIs used to hand out chewing gum in better times. Those "...dedicated evil forces..." will just keep coming, and will bring the conflict ever closer, until the USA learns to stay home and mind its own fucking business.