Reading about Iran and Shi`ism in the Mainstream Media, one would be tempted to conclude that this idea about the return of the Twelfth Imam as the Mahdi is a kooky one, held only by zealots like Ahmadinezhad and a handful of his ayatollah handlers.  If you think that, take a look at this story today in "The Times" of London:
"As darkness falls the floodlit domes and minarets of the great Jamkaran mosque begin to glow in translucent greens and turquoise. Coaches, cars and minibuses soon clog the four-lane highway leading up to the vast complex in the desert outside the holy Iranian city of Qom. By 10pm perhaps 200,000 pilgrims have poured into the concourse in front of the mosque – as they do every Tuesday night – for two hours of prayer and preaching. The pilgrims are young and old, men and women, the latter dressed in all-encompassing ink-black chadors. Many have brought babies and children, rugs and picnics. They have come from across Iran to pray for the reappearance of the Mahdi, the Hidden Imam, the 12th successor to the Prophet...." (http://www.timesonline.co.uk/tol/news/world/middle_east/article3556616.ece).
No, Mahdism is a very real and fervent belief for many Shi`is, not only in Iran but in Iraq, Lebanon and elsewhere.  Secular-mindeded State Department  types (as well their like-minded comrades in the Pentagon and intelligence agencies) may like to turn a blind eye to this, but reality has a way of proving a sharp stick.

Last month, on al-Aqsa (Palestinian) TV, Imam `Isa Badwan gave an interview in which he stated that the Mahdi had been born in the Palestinian territories four years ago.  How did he know? Because "someone whom is well known and whom I trust...told me that" a newborn  baby spoke and said "I am the man who will be killed by the Antichrist."  Badwan went on to say "the coming of the Antichrist will be preceded by the conquests of Rome...and Constantinople....These places will be conquered only by the righteous Mahdi. The Mahdi is from Palestine...." (http://www.memritv.org/clip/en/1708.htm
Observations:
1) Islamic  traditions say that Jesus spoke in the cradle, not the Mahdi; none of the three major compilers of hadiths about the Mahdi (Abu Da'ud, Ibn Majah, Ibn al-Tirmidhi) says that the Mahdi will do so.  Perhaps some of the commentators say this.  Or perhaps beliefs about Jesus have been transferred, in popular Islamic thought, onto  the Mahid.
2) The aformentioned compilers also say nothing of the Dajjal (which should be translated "the Deceiver," not really the "Antichrist") killing the Mahdi; and most commentators on Islamic eschatology have said, rather,  that Jesus will kill the Dajjal, not that the Dajjal will kill the Mahdi.
3) Of course the Mahdi's conquest of Rome and Constantinople was a common trope before 1453 among Islamic eschatologists.  But the Sunni Muslim Ottoman Turks took the former Christian imperial capital in that year, presenting something of a dilemma for Mahdists who cling to this tradition.  As I observe in my book Holiest Wars (p. 29, note 103): "For this to make sense in the modern world, the Muslim eschatologist must posit, as many Muslim fundamentalists...do, that the current government of Turkey is un-Islamic and deserves defeat, and that is major city Istanbul should be called by its former Christian name."
4) Mahdism is alive and well not only in Shi`i Iraq (as per my previous post) but in Sunni Palestine!
A special thanks to Patrick Poole, counter-terrorism blogger extraordinaire, for alerting me to this. His website is http://patrickpoole.blogspot.com/

I have been in contact with representatives of Sayyid al-Yamani, the head of the group Ansar al-Mahdi in southern Iraq.  Herewith are 11 questions I sent them, along with the verbatim answers:
1) What is Shaykh al-Yamani's relationship to the Mahdi?

"Sayid al Yamani (Ahmad al Hassan) is the son of Imam al Mahdi; Mohammed bin al Hassan (p), the twelfth Imam.
He is the promised Yamani ,the messenger and guardian of Imam al Mahdi; Mohammed bin al Hassan (p).

It would be useful for you to know that in the generations to come the rulers of the State of divine justice after twelve Imam Mahdi Mohammed bin Hassan (p) each of them is Mahdi by intestate Messenger of God Mohammad (pbuh).
Mahdi this title to the Imam Mohammed bin al Hassan (p), and his twelve sons , the first of whom is Sayid al Yamani (p). al Yamani true launch title Mahdi too.
2) Is al-Mahdi already here on earth?
Yes, Imam Mahdi Mohammed bin Hassan (p) is on the earth and live among the people but most of them do not know it and don't see him, and you can in this regard review many novels, which shows this sense.
3) Is al-Mahdi the same as the Twelfth Imam returned from ghaybah?
Yes, it is quite true to say that Imam al Mahdi is the twelfth Imam Mohammed bin Hassan (p) returned from ghaybah, and also true to say that his son Sayid al Yamani (Ahmad al Hassan) also can be named Mahdi.
4) Is al-Yamani's group Jund al-Sama' or Ansar al-Mahdi?
al Yamani group called Ansar al-Mahdi or Ansar Allah, supporters of Imam Mahdi (p) and supporters of Sayid Ahmed Hassan al Yamani; the messenger  and guardian and the Imam Mahdi (p).
We are unrelated to the so-called (Jund al-Sama' ), and there is great difference between us. Ansar al-Mahdi say that Ahmed Hassan (p) is the promised Yamani, a branch of Imam Mahdi Mohammed bin Hassan (p) and his son , while the group Jund al-Sama' deny the existence of Imam Mahdi Mohammed bin Hassan (p) in total.
5) Do al-Yamani and his group have any connection to Moqtada al-Sadr and the Jaysh al-Mahdi?
No relationship whatsoever between us and Moqtada al Sadr and his army Jaysh al-Mahdi, in a passage names as it is known.
6) What is al-Yamani's opinion of the American-sponsored Iraq government in Baghdad?
The government has to be based on the principle of the Governorship of God and must derive its legitimacy from God and from Imam Mahdi Mohammed bin Hassan (p).
7) What is al-Yamani's opinion of vilayet-i faqih in Iran?

Not valid as the answer became clear to you from the previous question.

8) What sort of state in Iraq does al-Yamani envision? A caliphate? A Mahdiyah?
Government, which al Yamani see it is the government based on the principle of Governorship of God. Whatever you want to call it as the term crossing, but the lesson in reality is substance and meaning.
9) What will be the Mahdi's role once he is revealed?

Imam al Mahdi will reveal justice and installment and will be published uniformity across the globe, and re-link the right relationship of God with humans after regrettably interrupted by the ego.

10) Do al-Yamani and the Mahdi expect Sunnis as well as Shi`is to be followers?
Imam al Mahdi and Sayid al Yamani expect followers from all sects and religions. They're for all and from all.
Their aim is to pull out the state of human rights in order to reach absolute perfection and worship to God alone, which is the real freedom.
11) Is al-Yamani's group peaceful or will it wage violent jihad if need be?
You have to know first that al Yamani group represent the real message of all messengers and prophets of God on earth.
If you look and consider the march movement of all prophets (p), you will realize that the message to heaven always pursues a peace advocacy and the one that is better, Koran says: ((Say Bring proof that you are truthful)), but you will always find that the bad governors and bad scholars and Slobs will face peaceful prophets with violence, force and displacement, and then - and only then - preachers forced to defend themselves and their faith.
And to answer this question, we would say yes,  the group of Al Yamani is designated to peaceful and that is all what they want from others."
Observations:
1) al-Yamani is not quite claiming to be the Mahdi, but to be his "son," "messenger" and "guardian."  In terms of charismatic power in an eschatologically-charged milieu, however, we might make note of the famous Vulcan saying "A difference which makes no difference is no difference."
2) The Mahdi is extant on earth and al-Yamani is in contact with him.  Remember that in Shi`i Islam the descendants of Muhammad through his son-in-law and younger cousin Ali (who married Fatimah' one of Muhammad's daughters) are Imams, or rightful leaders of the Islamic world.  Various Shi`i sects believe that one or another of these was (and will be) the true Mahdi; the largest group, the Shi`is of Iran and Iraq, believe that it was the Twelfth Imam, Muhammad, who will return at the end of time as the Mahdi. But before the Twelfth Imam went incommunicado in 941 CE (a silence lasting until today and known as the "Greater Occultation" [ghaybah in Arabic]), he was between 874 and 941 in a state of "Lesser Occultation" wherein he was unseen but still in contact with his followers.  If al-Yamani is saying the Mahdi is here and he is taking direction from him, then the Greater Occultation has ended and something approximating the Lesser one is back in effect.
3) Ansar al-Mahdi, despite Iraqi government statements otherwise, denies any connection to the seemingly more violent Jund al-Sama' (Soldiers of Heaven) and to the Sadrist Jaysh al-Mahdi.
4) Regarding the governments in Baghdad and Tehran al-Yamani seems to be saying "a pox on both their houses;" thus, both parliamentary democracy and the "rule of the religious jurists" are condemned as illegitimate. 
5) The Mahdi's supporters will not only be from all branches of Islam but also from "all sects and religions."  This is a sort of universalism not normally seen in Mahdist thought (and not at all in Salafi/Wahhabi Islam).
6) Ansar al-Mahdi--again, contra Iraqi government pronouncements--claims to be peaceful.  This puts it at odds with both Jund al-Sama' and with the Jaysh al-Mahdi, both of which have taken up arms against both the Baghdad government and U.S. forces.
7) It  may be that Ansar al-Mahdi--the popular support for which we really have no way of knowing--will evolve into a quietist movement (as with the Mahdaviyat movement of Sayyid Jawnpuri in 15th/16th c. Gujarat, India) over time.  Or frustration may boil over if the claims of al-Yamani are not recognized with the larger Iraqi society, and/or if the government tries to repress the group with force.  
8) Perhaps the U.S. forces should send a representative to meet with these folks.  If they are truly peaceful as they claim, another ally against the Sadrists and truly violent  groups would be a good thing to have.  Also, a Twelver Shi`i Mahdist group willing to critique the ayatollacracy in Iran might be valuable.

Not valid as the answer became clear to you from the previous question.

8) What sort of state in Iraq does al-Yamani envision? A caliphate? A Mahdiyah?
Government, which al Yamani see it is the government based on the principle of Governorship of God. Whatever you want to call it as the term crossing, but the lesson in reality is substance and meaning.
9) What will be the Mahdi's role once he is revealed?

Imam al Mahdi will reveal justice and installment and will be published uniformity across the globe, and re-link the right relationship of God with humans after regrettably interrupted by the ego.

10) Do al-Yamani and the Mahdi expect Sunnis as well as Shi`is to be followers?
Imam al Mahdi and Sayid al Yamani expect followers from all sects and religions. They're for all and from all.
Their aim is to pull out the state of human rights in order to reach absolute perfection and worship to God alone, which is the real freedom.
11) Is al-Yamani's group peaceful or will it wage violent jihad if need be?
You have to know first that al Yamani group represent the real message of all messengers and prophets of God on earth.
If you look and consider the march movement of all prophets (p), you will realize that the message to heaven always pursues a peace advocacy and the one that is better, Koran says: ((Say Bring proof that you are truthful)), but you will always find that the bad governors and bad scholars and Slobs will face peaceful prophets with violence, force and displacement, and then - and only then - preachers forced to defend themselves and their faith.
And to answer this question, we would say yes,  the group of Al Yamani is designated to peaceful and that is all what they want from others."
Observations:
1) al-Yamani is not quite claiming to be the Mahdi, but to be his "son," "messenger" and "guardian."  In terms of charismatic power in an eschatologically-charged milieu, however, we might make note of the famous Vulcan saying "A difference which makes no difference is no difference."
2) The Mahdi is extant on earth and al-Yamani is in contact with him.  Remember that in Shi`i Islam the descendants of Muhammad through his son-in-law and younger cousin Ali (who married Fatimah' one of Muhammad's daughters) are Imams, or rightful leaders of the Islamic world.  Various Shi`i sects believe that one or another of these was (and will be) the true Mahdi; the largest group, the Shi`is of Iran and Iraq, believe that it was the Twelfth Imam, Muhammad, who will return at the end of time as the Mahdi. But before the Twelfth Imam went incommunicado in 941 CE (a silence lasting until today and known as the "Greater Occultation" [ghaybah in Arabic]), he was between 874 and 941 in a state of "Lesser Occultation" wherein he was unseen but still in contact with his followers.  If al-Yamani is saying the Mahdi is here and he is taking direction from him, then the Greater Occultation has ended and something approximating the Lesser one is back in effect.
3) Ansar al-Mahdi, despite Iraqi government statements otherwise, denies any connection to the seemingly more violent Jund al-Sama' (Soldiers of Heaven) and to the Sadrist Jaysh al-Mahdi.
4) Regarding the governments in Baghdad and Tehran al-Yamani seems to be saying "a pox on both their houses;" thus, both parliamentary democracy and the "rule of the religious jurists" are condemned as illegitimate. 
5) The Mahdi's supporters will not only be from all branches of Islam but also from "all sects and religions."  This is a sort of universalism not normally seen in Mahdist thought (and not at all in Salafi/Wahhabi Islam).
6) Ansar al-Mahdi--again, contra Iraqi government pronouncements--claims to be peaceful.  This puts it at odds with both Jund al-Sama' and with the Jaysh al-Mahdi, both of which have taken up arms against both the Baghdad government and U.S. forces.
7) It  may be that Ansar al-Mahdi--the popular support for which we really have no way of knowing--will evolve into a quietist movement (as with the Mahdaviyat movement of Sayyid Jawnpuri in 15th/16th c. Gujarat, India) over time.  Or frustration may boil over if the claims of al-Yamani are not recognized with the larger Iraqi society, and/or if the government tries to repress the group with force.  
8) Perhaps the U.S. forces should send a representative to meet with these folks.  If they are truly peaceful as they claim, another ally against the Sadrists and truly violent  groups would be a good thing to have.  Also, a Twelver Shi`i Mahdist group willing to critique the ayatollacracy in Iran might be valuable.

Not valid as the answer became clear to you from the previous question.

8) What sort of state in Iraq does al-Yamani envision? A caliphate? A Mahdiyah?
Government, which al Yamani see it is the government based on the principle of Governorship of God. Whatever you want to call it as the term crossing, but the lesson in reality is substance and meaning.
9) What will be the Mahdi's role once he is revealed?

Imam al Mahdi will reveal justice and installment and will be published uniformity across the globe, and re-link the right relationship of God with humans after regrettably interrupted by the ego.

10) Do al-Yamani and the Mahdi expect Sunnis as well as Shi`is to be followers?
Imam al Mahdi and Sayid al Yamani expect followers from all sects and religions. They're for all and from all.
Their aim is to pull out the state of human rights in order to reach absolute perfection and worship to God alone, which is the real freedom.
11) Is al-Yamani's group peaceful or will it wage violent jihad if need be?
You have to know first that al Yamani group represent the real message of all messengers and prophets of God on earth.
If you look and consider the march movement of all prophets (p), you will realize that the message to heaven always pursues a peace advocacy and the one that is better, Koran says: ((Say Bring proof that you are truthful)), but you will always find that the bad governors and bad scholars and Slobs will face peaceful prophets with violence, force and displacement, and then - and only then - preachers forced to defend themselves and their faith.
And to answer this question, we would say yes,  the group of Al Yamani is designated to peaceful and that is all what they want from others."

Aswat al-`Iraq [Voices of Iraq] reports that over the weekend armed supporters of Ahmad al-Yamani were captured in Karbala (http://www.aswataliraq.info/).  Shaykh al-Yamani, who has gone underground--rumours of his death having been greatly exaggerated, I have  been assured by members of his group who contacted me via email--is the leader of one of the three major overt Mahdist groups in Iraq today, Ansar al-Mahdi.  The other two are Muqtada al-Sadr's Jaysh al-Mahdi and the more secretive Jund al-Sama', whose leader Abu Mustafa al-Ansari was reported killed earlier this year leading his supporters in attacks against American and Iraqi government forces.  The government in Baghdad claims that Ansar al-Mahdi is a violent group, but members have informed me that they are in truth a peaceful group and are being scapegoated by the Iraqi central government. It is hard to know whom to believe, and hard open intelligence on these groups is extremely difficult to come by. Some Iraqi bloggers even seem to think that Jund al-Sama' is an offshoot, or more violent faction, of Ansar al-Mahdi (think Hamas and Islamic Jihad). 


The situation is further complicated by the recent statement of Muqtada al-Sadr's that "some close followers have split from his movement" (http://www.iht.com/articles/ap/2008/03/07/news/Iraq-Al-Sadr.php).  A number of possible reasons for such defections comes to mind:
*al-Sadr's cease-fire dissatisfies the more zealous
*al-Sadr's willingness, even in a limited fashion, to participate in the Iraqi parliamentary system is seen as selling out by some
*al-Sadr may be seen as too pro-Iranian
*al-Sadr may be seen as insufficiently eschatological--too much Jaysh (army) and not enough al-Mahdi.
The biggest questions for U.S. and Iraqi forces would be: 1) Are these disgruntled Mahdists abandoning the field or (as is more likely) joining up with Ansar al-Mahdi or Jund al-Sama'?  And even more importantly 2) How much worse will it get WHEN--not if--someone actually declares himself  the Mahdi, not simply his precursor?