i want to bring in matt olson, the former head of the national well. what we may be seeing here is precisely a reaction to the kind of progress that the u.s. military says is being made in iraq. you see a strategic lashing out in europe. >> i think that's exactly right, george. there has been progress on the ground in iraq and syria, but as these groups, as isis comes under that kind of pressure, the concern is that they will take steps to show their relevance and to carry out the kind of attack that we saw this morning in brussels. i think as martha raddatz said quite correctly, it's very difficult to stop one of these attacks at an airport or at a train station. targets. the key is getting good intelligence so that we can they're able to be carried out. >> which means right now, richard clarke, the pressure is going to be increased on belgian authorities to try and get more information from the man they now have in custody, that attacker from paris, salah abdeslam. >> they have him in custody and they've been questioning him since friday. they undoub