The end times core teaching of Protestant fundamentalism.

"Dispensational" refers to dividing the faith's sacred history into distinct periods, called dispensations.

"Premillennialism" is the view that Jesus will soon return, defeat the Antichrist and establish a thousand-year reign of peace.

Put together, you have a package quite similar to the Shia faith concept of the 12th or "hidden imam" whose return signals a similar and universal period of violence followed by salvation.

Dispensational premillennialism was developed by the British theologian John Nelson Darby (1800-1882) and spread across the U.S. after the bloody Civil War (go figure). The incredibly popular Left Behind book series underscore how today dispensational premillennialism "is the most popular form of prophecy belief in the United States, informing (among other things) conservative Christian support for the state of Israel."

From Stephen Prothero's Religious Literacy.

Remember that when you're being sold the war with Iran: some are more predisposed for this sale than others, meaning Ahmandinejad's brand of religious determinism is matched by plenty on our side.

Which side is mere "belief" and which side is frightening "irrationality"?

Well, that depends now doesn't it?