defense to prevent future attacks.
A way to ensure an attack would not happen is to strike and terminate the threat. Terminate anything in this world is a cruel decision, but when it threatens globally, then it must be done. United States considered putting United Nation at a higher power to solve terrorist problems, but people also worried that it would bring political problems. Some Americans believed that United State should do it by itself to ignore conflicts between other countries opinions.
Increase military actions to go against potential enemies and defend terrorist can protect the Americans. Add security to prevent future terrorist attack is a way to deal against terrorism, but it would not stop the terrorists. Defend homeland can only increase the security of the nation, but terrorists could still possibly invaded and created another crisis like 9/11.
Perhaps people think United State is safe enough, but the public never knows. There could be terrorists among the people walking on the street or anywhere else. Someone people said to fight terror with terror, that might be a solution, but it is necessary to protect the natural rights people have, not to doubt base on race. However, the people considered to hide in the shell would not realize to strike, only if when the shell breaks they would notify everything is too late.