We (Customs and Border Protection) don't have nearly the manpower necessary to protect our borders properly. Foe example, when an individual comes to the US from a "suspect country" i.e. Iran, we register him before we admit him. We gather his address info, contacts in the US, take prints, photos, etc. But, we don't have the manpower to follow up on these registrants. (E.G. Muhammed Al Carbomber comes from JOrdan, says he's staying at the Palmer House for business meetings...we don't have the personnel to call the hotel, confirm reservations, etc.)