Yes, the there is a terrorist threat. Many countries and cultures strongly dislike the United States and how we live. They feel that it is harming or offensive to their God or their culture and they will try to attack us to fix us. Unfortunately for them, we are too numerous and bright to genuinely be harmed in any long term way for this method to work for terrorists.
...But that's just what they are... Radicals. There are plenty of angry religious, nature, homophobic, and many other types of radicals in the U.S. as well. The belief that all other countries are out to wipe Americans off the face of the planet is just a government fear campaign to stir up funds, control and obedience.
Terrorists are only a myth. Them, and Muslims, don't exist. The were made up as an excuse for the army to move in and attack the Middle East desert...
Like the Oceans Caligula faced, and the Forests and fields that France, Germany, Britain, and the US had to face... The Middle East desert is rebelling and must be stopped.