Terrorists watch TV news also

At least 37 dead in London from terrorist blasts



So the U.S. raises its terror alert after the destruction has been done? Why do it after the destruction and why display the raised terror alert to the entire world? Would terrorists not just attack when the terror alert drops? If it is used as a deterrence, why not always have a raised terror alert? And if there is always a raised terror alert, why have a terror alert at all? These are just my thoughts, but they seem reasonable. Right?

If the terror scale were to be a useful tool... predict WHEN an attack would happen and report it to the proper authorities, in the proper place, and stop the attack. Don't report clues to the entire world...including terrorists.