A few weeks ago I spoke at the U.S. Army War College on Mahdism and Shi`i jihad in both theory and historical praxis.  To make a long story short(er): With the disappearance of the 12th Imam in the 10th c. CE, Shi`i jihad for the most part over the next millennium was placed offline, in passive mode, awaiting the return of the Imam as Mahdi to wage it.  There were notable exceptions, such as Shah Isma'il, the 16th c. founder of  the Safavid dynasty in Iran, who waged divinely-directed jihad in the absence of the 12th Imam (largely in order to fight the Sunni Ottomans, one might argue)--but by-and-large most Shi`i clerics (Iranian and Iraqi) allowed only jihad-i `ilmi wa-tablighi ("jihad of knowledge and propaganda"), and prohibited not just jihad-i ghalaba ("victorious jihad") but also jihad-i istimata ("jihad of death/desperation").  This began to change in the 19th c. as "infidel" nations--most pressingly Orthodox Christian Russia--began intruding into Shi`i territories, which prompted many Twelver Shi`i clerics to issue fatwas legitimizing defensive jihad in the absence of the Imam Mahdi. Among the notable characteristics of this defensive jihad sans Mahdi are the following:
1) The dual aim of preventing non-Muslims from ruling over Muslims, and ejecting non-Muslims from Muslim territory
2) Dhimmis--"protected" Christian and Jewish minorities under Muslim rule--are no longer sacrosanct
3) Any hudnah agreed to with non-Muslims is revocable before its term runs out
4) It's permissible to kill Muslims who assist the non-Muslim ("infidel") invaders
5) Non-traditional warfare--"grenades, flooding," and general scorched earth policies--is allowed (the 19th c. version of WMDs, easily updatable--using ijtihad--to today)
6) Everyone (including women and children) must fight.
This mode of Mahdi-less jihad was employed by the Iranians in their Gulf war against Saddam's invading armies from 1980-88, and occasionally by their co-religionists from Hizbullah in Lebanon against us and other Westerners.  So far in American-occupied Iraq such jihad has not been directed against U.S or Iraqi government forces from the Shi`i side (although of course AQI and its epigones have done so from within a jihadist Sunni worldview). 
That may be about to change, however.  According to the Associated Press, yesterday, Grand Ayatollah Ali al-Sistani "has been quietly issuing religious edicts declaring that armed resistance against U.S.-led foreign troops is permissible"
(http://ap.google.com/article/ALeqM5jQ7to4Zhf0BTz9HqeVbjvvgx9LUQD90QS17O0).
Aside from questioning the logic of AP's reporting that "so far, al-Sistani's fatwas have been...issued verbally and in private"--since the very definition of a fatwa, or official religious proclamation, mandates that it must be public--this is indeed an alarming development, marking as it does not only the 1) official legitimation of Shi`i jihad in Iraq but also 2) a dangerous convergence between Shi`i and Sunni jihad, as well as 3) a possible trip-wire for the explosion of full-blown Mahdism in Iraq (and perhaps the larger Shi`i world).

According to al-Arabiya News, President Ahmadinezhad's constant references to Imam Mahdi are not going over well with some of the ayatollahs:
"Iranian scholars have told President Mahmoud Ahmadinejad to stick to more worldly issues after he said the "hidden imam" of Shiite Islam was directing the country's affairs...in a speech to theology students broadcast by state television on Monday, Ahmadinejad went further than ever before in emphasizing his belief that the Mahdi is playing a critical role in Iran's day-to-day politics. 'The Imam Mahdi is in charge of the world and we see his hand directing all the affairs of the country,' he said in the speech, which appears to date from last month but has only now been broadcast....Two leading scholars retorted that Ahmadinejad would be better off concentrating on Iran's social problems -- most notably its double-digit inflation -- than indulging in such mystical rhetoric. 'If Ahmadinejad wants to say that the hidden imam is supporting the decisions of the government, it is not true,' said Gholam Reza Mesbahi Moghadam, the spokesman of the pro-reform Association of Combatant Clerics. 'For sure, the hidden imam does not approve of inflation of 20 percent, the high cost of living and numerous other errors,' he said, according to the Kargozaran daily. Ali Asghari, a member of the conservative Hezbollah faction in parliament, told the president not to link the management of the country to the imam. 'Ahmadinejad would do better to worry about social problems like inflation ... and other terrestrial affairs,' the Etemad Melli daily quoted him as saying....Earlier this year, Iran's former top nuclear negotiator Hassan Rowhani complained that superstition was growing in the country and that people were even putting out food for the Mahdi in case he returned that very night" (http://www.alarabiya.net/articles/2008/05/07/49515.html).
Observations:
1) Ahmadinezhad is a true believer in, if not the imminent appearance of the Mahdi, at least his active involvement in the world today, whereas many Iranians (including a number of ayatollahs, it seems) are content to relegate his coming to some nebulous point in the future. There is an analog here to Christianity, which has as a staple belief in all three creeds (Athanasian, Nicene and Apostles') Jesus' Second Coming but yet is divided into a global majority (Catholics, Orthodox, Lutherans, Anglicans/Episcopalians--altogether some 1.5 billion of the world's 2.3 billion Christians) that believes this yet does not incorporate it into everyday political analysis and action, and a minority (Evangelicals, "Fundamentalists," many Pentecostals--folks who tend to have "In The Event of Rapture, This Car Will Be Unmanned" bumper stickers) which expects His return any day now.  President Bush is often derisively lumped into the latter category, but in point of fact, as a Methodist, would fall into the former.  As I've said before, President Bush has never gone to the well of the United Nations and prayed "come, Lord Jesus." But Ahmadinezhad has done this vis-a-vis the Mahdi more than once.
2) Interesting that Iran has an "Association of Combatant Clerics."  Can you imagine such a parallel organization in the Christian world? True, we've had them--during the Crusades.  But they don't exist anymore--which puts the lie to all those recent tomes (Harris, Hitchens, Dworkin, et al.) on how all religions (Christianity every bit as much as Islam) are equally responsible for violence and intolerance in the modern world.
3) Even (some of) the ayatollahs in Iran would prefer a "Problem-Solver-in-Chief" to a "Mystic-in-Chief."
4) I hope those people putting food out for the Mahdi are treating him better than I did Santa Claus when I was a kid--I used to leave out bologna sandwiches with ketchup on Christmas Eve and they were always gone the next morning.  I always thought it an uncanny coincidence that my father also liked the same fare.  In any event, let's hope the Mahdi has better tastes and more creative chefs.

Two recent developments on the international stage would appear to be unrelated but, on closer analysis, are linked and important.  1) As "The Economist" reports in the April 26th issue, the new Human Rights Council at the U.N. is "[d]ominated by the Organisation of the Islamic Conference and the Non-Aligned Movement," such that "last month...the council's Islamic members, backed by Russia and China, pushed through a resolution saying free speech should be limited out of 'respect for religions and beliefs'" (meaning: no more Muhammad cartoons, or else).  In creating the HRC "what no one foresaw was the extent to which Islamic states would use this...to single out Israel" ("The U.N. and Human Rights.  A Screaming Start").  Actually, a number of us in the States foresaw this; and our fairly objective journalistic friends over in London are understating the case to say that the OIC uses the HRC merely to go after Israel; that free speech-bashing resolution was aimed at the larger West.  2) In an event ignored by the Jurassic Media in the U.S., the head of Iran's Islamic Cultural Relations Organization--aptly named MAHDI Mostafavi--met with Pope Benedict XVI shortly after his return from the U.S., in order to foster relations and dialogue between Roman Catholics and Shi`i Muslims.  He even presented the Pope with a copy of the Qur'an (http://english.irib.ir/index.php?option=com_content&task=view&id=10728&Itemid=42).
Observations:
1) Geopolitically, these two developments illustrate, once again, the global struggle between Sunni Muslims--which the OIC largely is, being based in Jeddah, Saudi Arabia--and the Shi`a, led by Tehran.
2) We in the West, and Americans in particular, are frankly wrong to label Shi`i Iran (and Iraq) as the font of all evil and fanaticism emanating from the Islamic world. This is a hangover, I think--at least among Americans--of the hostage crisis in Iran during 1979-80, when Ayatollah Khomeini became for many in this country the face of Muslim extremism.  At the risk of overgeneralization, it is Shi`ism that historically tends to be more open to theological and even political debate than Sunnism, because of the Shi`is status as a minority branch of the religion and also because of the survivial therein of the idea of ijtihad, "exegesis...on matters of theology and law" (Haim, The Shorter Persian-English Dictionary).  I would argue that when (not if) a revolution occurs in Islamic political thought--a Muslim "Enlightenment"--it will start in the Sh`i world (if it hasn't already, in the arguments among ayatollahs in Iraq about the wisdom and applicability of vilayet-i faqih).  This is not to deny the sponsoring of groups like Hizbullah and Jaysh al-Mahdi by the Islamic Republic. But note that while the OIC is working to curtail a fundamental human right--freedom of speech--Tehran is sending delegates to meet with the leader of 1.1 billion Christians.  Quite a contrast.
3) Wouldn't it behoove us (the U.S.) to consider re-establishing official diplomatic relations with Iran? Even without succumbing to a Barack Obamaesque naievete about international relations, one cannot help but observe holding grudges in geopolitics is not the basis of a realpolitick foreign policy.  Vietnam is, if not an ally, at least a friend of America now--and there's a lot more blood under the bridge between us and the Vietnamese than between us and the Iranians.  And we had, and have, diplomatic relations with countries Washington deems every bit as, if not more, unsavory. 

In the latest issue of Parameters (Spring 2008), the U.S. Army War College's quarterly journal, Major Pat Proctor argues that "dire warnings....of an emerging 'Shia Crescent,' led by Iran and encompassing Lebanon, Syria and Iraq" are, well, "mythical"--especially in the case of Syria, which is not really Shi`i at all but rather Alawi (or, as the sect is sometimes called, Nusayri).  Major Proctor is correct about the Syrian Alawis (who were actually declared non-Muslims in a fatwa by the famous Sunni jurist Ibn Taymiyah some seven centuries ago). However, he overstates the weakness of Shi`i Hizbullah in Lebanon and understates the Twelver Shi`i ties between Iraq and Iran.  And his analysis ignores the Shi`a movement in several other Arab countries, most notably Yemen, whose popluation is not much smaller than Saudi Arabia's (23 million to about 27 million), of which a large minority--perhaps as high as 40%--is Shi`ite, of the Zaydi persuasion.  Yes, few people even know about the Zaydi, or Fiver, branch of Shi`ism but it was the official religion of Yemen for a millennium or so, until 1962's republican take-over.  The disenfranchised Zaydi Shi`a took up arms some years ago, under the leadership of one Abd al-Malik (or Husayn) al-Houthi, and over this past weekend 19 Yemenis were reported killed in clashes between "rebel" Shi`i forces and government troops (http://www.africasia.com/services/news/newsitem.php?area=mideast&item=080504200319.ru5udpgq.php).  
Yemen is strategically located on the Arabian peninsula and is right across from the Horn of Africa.  Before we consign the "Shi`a Crescent" to chimerical status, Yemen needs to be factored into the equation.