Closing loopholes?

While I agree that airports must be secured against potential terrorist threats, the suspension of programs allowing visa-free stays at U.S. airports whle en transit is a curious one because the government states that those most effected by the new rules will be people from Brazil, Mexico, South Korea, the Phillipines, and Peru. Strange but I don't think any of the terrorists associatated with 9/11 were from one of those countries. Also, the suspension does not affect passengers from 27 "visa-waiver" countries, mostly in Europe and the Far East and Southeast Asia. Whatever the plan, portential terrorists will find a way around the regulations. The "law" has never prevented a crime from occurring anywhere nor at anytime. There seems to be some muddled thinking in Washington once again.