served as senior counterterrorism advisor to former vice president dick cheney. it s striking to me how similar this attack was two things that we have seen in the past like nice france, which was so horrific last summer. a van driving down the sidewalk, a busy pedestrian area and it s working with a vehicle trying to hit as many people as possible. the terrorists have found the perfect weapon that requires no training. i think there s a bigger point here in the sense that western society, europe, united states can t play perfect defense. we can to stop all vehicles and we can t stop all crowds. what we have to do is maintain our offense of posture, stay focused on the sanctuaries. this is why the strategy to stabilize syria, to finish off isis as a state is so important. that s why the broader strategy, we are at war in a global war against islamic extremism.