When I see attacks like the one in Glasgow today, I can't help but to think we're living on borrowed time here. These acts are not hard to commit, require little to no sophistication and there are more than enough willing terrorists out there. So why the relative silence? I can only guess that Al Qaeda and their sympathizers see more value in a huge attack on the scale of 9/11 than a relatively small one. But we're on borrowed time and we aren't remotely ready for it.