Department of Homeland Security Prevents Terrorist from Entering the U.S. As we all know, since September 11, 2001 the U.S. has been much more vigilant in defending itself against terrorist attacks.  nbsp;In addition to bombing the shit out of the Middle East, we have also established the Department of Homeland Security whose responsibility it is to defend us from terrorists. They have so far done a stellar job, as the U.S. has yet to be hit by another terrorist attack.  nbsp;But the ever-vigilant Department of Homeland Security is not resting on its laurels. Recently, they prevented the terrorist supporter Yusef Islam from entering the United States.