Many current UK and US politicians have openly said entering the Iraq War was a mistake. In fact, it has triggered introspection from scholars to involved officers.

"There was a sense in which after Bosnia and Kosovo and Sierra Leone and the rapid overthrow of the Taliban, we and the Americans thought intervention was relatively easy. It wasn't without its costs but it was something we could achieve relatively quickly and provide the very positive humanitarian outcome for the people involved on the ground, whether it is in Kosovo or Sierra Leone or wherever. And that was the expectation in Iraq and, of course, entirely the opposite was the case," said Malcolm Chalmers, department director general of Royal United Services Institute in UK.