On the George W. Bush Administration Apparently Believing that the Country's Security State Which Was Good Enough During the Cold War Somehow Wasn't Sufficient for an Enemy Whose Most Lethal Weapons (Save for the Planes, of Course) On 9/11 Were Some Box-Cutters - Enter the Homeland Security Department

 It was supposed to be temporary (til al Qaeda and later ISIS were destroyed - an accomplishment that Trump has touted, as I recall) but just like pretty much every other department in history, forever seems like a much safer bet.