There must have been 100,000 Iraqis killed in sectarian violence.
The responsibility of a situation that can be wholly laid at the feet of the US and UK govts.
What to do?
Negotiate. Talk to the combatants (all of them, Al Shahbab, Al Queda, Boko Harram, ISIS all of them), and first of all get them to stop fighting on their terms, not trying to enforce “not fighting” by us. Second, probably re-arrange these ‘countries’ so that they more accurately reflect tribal and religious needs. Accept the fact that both Saudi Arabia and Iran are the local power-brokers and get them involved in constructive dialogues. Above all else, security for civilians and the end of violence.
Rather than export violence, export knowledge, schooling, power, time…
Is what I’d do for a kick off.