ISIL aren't going to be defeated with bullets and bombs. They will work up to a point, but analysts are already suggesting that the Metrojet bombing, a string of suicide attacks in Beirut, and now the wave of attacks across Paris is ISIL pushing back. They have taken losses in recent weeks and months - starting with Kobane, the Peshmerga offensive across northern Iraq, Russia's entry into the conflict, and in recent days, the loss of a Syrian air force base. They're going to push back; they need to push back to demonstrate that they are not beaten and will continue to fight. This may well be their response. And if our campaign against them is limited to air strikes and supporting counter-insurgencies, then this will happen again.