Thanks to Mahmoud Ahmadinejad, the president of Iran, a new word has entered the political vocabulary: mahdaviat.

Not surprisingly, it’s a technical religious term. Mahdaviat derives from mahdi, Arabic for “rightly-guided one,” a major figure in Islamic eschatology. He is, explains the Encyclopaedia of Islam, “the restorer of religion and justice who will rule before the end of the world.” The concept originated in the earliest years of Islam and, over time, became particularly identified with the Shi‘ite branch. Whereas “it never became an essential part of Sunni religious doctrine,” continues the encyclopedia, “Belief in the coming of the Mahdi of the Family of the Prophet became a central aspect of the faith in radical Shi‘ism,” where it is also known as the return of the Twelfth Imam.

Mahdaviat means “belief in and efforts to prepare for the Mahdi.”

In a fine piece of reporting, Scott Peterson of the Christian Science Monitor shows the centrality of mahdaviat in Ahmadinejad’s outlook and explores its implications for his policies.

When he was still mayor of Tehran in 2004, for example, Ahmadinejad appears to have secretly instructed the city council to build a grand avenue to prepare for the Mahdi. A year later, as president, he allocated US$17 million for a blue-tiled mosque closely associated with mahdaviat in Jamkaran, south of the capital. He has instigated the building of a direct Tehran-Jamkaran railroad line. He had a list of his proposed cabinet members dropped into a well adjacent to the Jamkaran mosque, it is said, to benefit from its purported divine connection.

He often raises the topic, and not just to Muslims. When addressing the United Nations in September, Ahmadinejad flummoxed his audience of world political leaders by concluding his address with a prayer for the Mahdi’s appearance: “O mighty Lord, I pray to you to hasten the emergence of your last repository, the Promised One, that perfect and pure human being, the one that will fill this world with justice and peace.”

On returning to Iran from New York, Ahmadinejad recalled the effect of his U.N. speech:

one of our group told me that when I started to say “In the name of God the almighty and merciful,” he saw a light around me, and I was placed inside this aura. I felt it myself. I felt the atmosphere suddenly change, and for those 27 or 28 minutes, the leaders of the world did not blink. … And they were rapt. It seemed as if a hand was holding them there and had opened their eyes to receive the message from the Islamic republic.

What Peterson calls the “presidential obsession” with mahdaviat leads Ahmadinejad to “a certitude that leaves little room for compromise. From redressing the gulf between rich and poor in Iran, to challenging the United States and Israel and enhancing Iran’s power with nuclear programs, every issue is designed to lay the foundation for the Mahdi’s return.”

“Mahdaviat is a code for [Iran’s Islamic] revolution, and is the spirit of the revolution,” says the head of an institute dedicated to studying and speeding the Mahdi’s appearance. “This kind of mentality makes you very strong,” observes the political editor of Resalat newspaper, Amir Mohebian. “If I think the Mahdi will come in two, three, or four years, why should I be soft? Now is the time to stand strong, to be hard.” Some Iranians, reports PBS, “worry that their new president has no fear of international turmoil, may think it's just a sign from God.”

Mahdaviat has direct and ominous implications for the U.S.-Iran confrontation, says an Ahmadinejad supporter, Hamidreza Taraghi of Iran’s hard-line Islamic Coalition Society. It implies seeing Washington as the rival to Tehran and even as a false Mahdi. For Ahmadinejad, the top priority is to challenge America, and specifically to create a powerful model state based on “Islamic democracy” by which to oppose it. Taraghi predicts trouble ahead unless Americans fundamentally change their ways.

I’d reverse that formulation. The most dangerous leaders in modern history are those (like Hitler) equipped with a totalitarian ideology and a mystical belief in their own mission. Mahmoud Ahmadinejad fulfills both these criteria, as revealed by his U.N. comments. That combined with his expected nuclear arsenal make him an adversary who must be stopped, and urgently.