After last week's attack in Saudi Arabia, I suspect that the USA should put its guard up.

What I expect is: A group of coordinated truck bomb attacks such as Tim McVeigh did in Oklahoma.

What I might also expect: A few of Saddam's nerve gas shells loosed in enclosed public places.

Countermeasures: Watch truck rentals in USA, Canada, and Mexico. Watch sales of ammonium nitrate or other explosives in large quantities to persons who have no legitimate use for them. Find the rest of Saddam's poison gas arsenal before Al Qaeda does. Obviously, watch out for suspicious persons entering the USA. Also look into container traffic at seaports.