Isis is an escalating threat that’s growing and worsening. The longer it takes to deal with [it], the further its influence spreads, the more recruits it attracts, the harder it is to dislodge from the cities it has captured, the more deeply it’s able to harm the communities it controls, the more civilians will ultimately be killed, and the greater the military response ultimately required to defeat it. This is a case when the job will become much harder, require much more lethal force and do more harm as time goes on: we have to go hard, now, or we’ll end up having to go in much harder, and potentially on a much larger scale, later – or accept defeat. The risk is not that Isis will somehow restart its blitzkrieg and conquer Iraq and Syria. Rather, the threat is that of a regional conflagration if there’s no effective international (which, like it or not, means western-led) response.