With followers in parliament and a powerful militia at his disposal, Shiite cleric Muqtada al-Sadr's is vital to the future stability of Iraq.

JIM LEHRER: The al-Sadr story, now, more than ever, the Iraqi Shiite cleric Muqtada al-Sadr is at the center of attention in Iraq once again. Sunday's joint U.S.-Iraqi raid in Baghdad killed several men believed to be his followers. His Mahdi army is among the largest of all the sectarian militias, and al-Sadr and his 30 loyalists in the new Iraqi parliament may be key to forming a new Iraqi government.

To discuss al-Sadr, Judith Yaphe, a former Middle East analyst at the CIA, now a senior fellow at the National Defense University, and Juan Cole, professor of history at the University of Michigan, author of "Sacred Space and Holy War" about modern Shiite history and politics.

Ms. Yaphe, how important a development is this weekend conflict between al-Sadr's folks and U.S. forces?

JUDITH YAPHE: Well, it could be very important, depending on who was responsible for what, but perception is more important than reality in this region.

But a confrontation with him could trigger more serious fighting and could put us in a very difficult position. Sadr controls much of Shiite section of Baghdad, the southern section, where 2.5 million Shia live.

It could be a high-risk proposition; it could trigger further fighting; it could be a tipping point. On the other hand, they could be out so far they say, "Whoops, we've made a mistake. We need to pull back a bit."

JIM LEHRER: Who says, "We made a mistake," the U.S. and the Iraqi forces or al-Sadr?

JUDITH YAPHE: Well, that's a good question. Both sides, I would guess. "I'm sorry I didn't mean to do that."

But I would think that how far they want this go, do they want this to turn into civil war? Do they want it to turn into a much more widespread fighting and killing? My guess is not, because then things really do spin out of control.

JIM LEHRER: OK.

JUDITH YAPHE: And neither the United States, nor Sadr, nor his patrons would like that.

JIM LEHRER: Professor Cole, do you agree this is a critical point?

JUAN COLE: Well, it's a turning point, in a way. Up until fairly recently, for the most part, the mainstream of the Shiite community in Iraq has felt that the United States was on their side, that they were allies.

Now, in the wake of the blowing up of the Golden Shrine in Samarra, the sectarian violence that occurred there after, the U.S. is perceived increasingly to be intervening on the side of the Sunnis.

And this incident that occurred where this Shiite religious building appears to have been attacked did kill others than just Sadr's followers. At least one man who was killed belonged to the Dawa Party, which has an office in that area. And so the prime minister of Iraq, Ibrahim Jaafari, belongs to the Dawa Party.

So the reaction to this incident is not coming just from Sadr's people; it's coming from the Shiite political elite across the board. And the Iraqi official television channel was very critical of the U.S. The municipal authorities of Baghdad came out and announced that they won't cooperate with the U.S. until this is cleared up. People have called for an investigation.

So this is really an issue of: What is the relationship of the U.S. forces in Iraq to the Shiite mainstream? Because they cannot stay there if the Shiites turn on them.

JIM LEHRER: So you agree, though, with Ms. Yaphe, then, that the perception is more of an issue now than what the reality was. In other words, you're saying everybody in the Shia community is just assuming the U.S. forces were at fault here, right?

JUAN COLE: Yes. The way it's been portrayed, from all accounts on Iraqi television and in the press, is that the U.S. forces, alongside perhaps some Iraqi forces, burst into this Shiite religious edifice and shot up innocent worshippers.

That seems strange, but that is the account that's coming out. The U.S. military is now denying it; it's saying that they were along for support, that the people who were killed were subsequently -- the bodies were rearranged to make it look like a massacre.

But then that raises questions of competence. You know, why would you conduct this operation and then just leave and allow the other forces to represent it for you?

JIM LEHRER: So, Ms. Yaphe, as you say, perception is going to rule the day here, right, until an investigation clears it up, and assuming that it could? Remind us again about al-Sadr. What do we need to know about this guy?

JUDITH YAPHE: He comes from a very well-known religious family, but also one that's been involved in opposition politics. His father had been appointed by Saddam to be head of a major mosque in Baghdad, but then the father sort of did what Becket did.

Once he became God's man, he was no longer the king's man. And he started to push for restitution of certain rights, Friday public prayer worship, for example, things that Saddam had not allowed.

And then Saddam decided that was that, and there was a terrible car accident in which Muqtada al-Sadr's father and two brothers were murdered.

JIM LEHRER: So Saddam Hussein's people killed him.

JUDITH YAPHE: Basically they were killed by Iraqi intelligence. This projects, of course, Muqtada al-Sadr, whose popularity, if you will, comes from the fact that he comes from a very important, highly respected family. In addition, he's becoming a force to be reckoned with. But he gets respect for a lot of different reasons.

What is not so clear to me and to many others is how much he is in charge of this movement, if he's in control, or if he's not, and who is advising him, because he's pulled some very skillful maneuvers. He's had a very successful tour, for example, of Lebanon, of Syria. I think he was in Saudi Arabia when the mosque in Samarra was blown up, and he raced home, of course. But he's done some very clever organization.

JIM LEHRER: So he's on the rise? He's on the rise, you think, as far as power?

JUDITH YAPHE: It looks that way. But he is behaving, in a sense, that he has his loyalists, loyalists who are the parliament. He didn't run for parliament. Whether he sees that as part of his future or the fact that he's really a very junior cleric who is a long way from having the kind of religious credibility and authority, but if he has it in mind, he would want to be in the parliament, I would guess.

JIM LEHRER: Juan Cole, where would you put al-Sadr in the power struggle that's going on now, the civil power struggle that's going on within Iraq right now?

JUAN COLE: Well, Sadr gave an interview on Al Jazeera in which he said that he's gone beyond now the early stages of his movement, the first of which was protest and the second of which was military, and now he's in the political phase.

He says that his movement is dedicated to mainstream politics, to parliamentary politics, and they're working to end what he calls the foreign military occupation of Iraq. That is, is he wants to get the U.S. troops out of the country.

He was given 30 seats in the United Iraqi Alliance in parliament. And his bloc has emerged as a kingmaker. He was able to swing the party towards Ibrahim Jaafari for a second term as prime minister, as candidate. That really is the Sadr movement's doing.

So he's gone from hiding out from the Marines in that shrine in Najaf now to being a kingmaker in Iraqi politics. His movement is largely slum-dwellers, ghetto youth with guns. I don't think he controls it very closely. I think it's a movement and not an organization, and there is always danger of it getting out of his control.

He himself is calling for a calm reaction to these events. He says that his movement must continue the political struggle to end the occupation.

JIM LEHRER: What do you make of comments that, if he were to align himself with the ongoing al-Qaida insurgency, it could be a devastating thing for everybody? Is that likely to happen?

JUAN COLE: No, Muqtada al-Sadr is at daggers drawn with the insurgency. The insurgency is made up of maybe 50 cells, and they span the spectrum from hard-line neo-Baathists, to Arab nationalists, to hard-line Salafis or Sunni Muslim revivalists.

Most of those groups have a history of attacking and killing Shiites. Muqtada really wants to destroy them, I think.

The alliance that he has sought on the Sunni side has been with the Sunni sort of mainstream fundamentalists, the Islamic Iraqi Party, the Association of Muslim Scholars. These are hard-line Sunni fundamentalists, but they are not openly involved, at least, with the guerilla movement.

JIM LEHRER: Do you read it the same way, Ms. Yaphe?

JUDITH YAPHE: Yes, I do. It gets confusing as to which fundamentalist he's with, but I think Juan has it absolutely correct.

He's a very controversial figure, in the sense that -- and contradictory. He is close to the Iranians. He, in a visit to Iran a couple of months ago, said an attack on Iran would be an attack on Iraq on us, and we would defend Iran.

On the other hand, he's also known for not wanting to see replication in Iraq of everything that is done in Iran. He wants to be independent of them.

One of the other significant things, I think, is that his differences reflect different splits within the Shia movement. There is no monolithic Shia political movement, but there are factions.

He heads or represents a strong and a powerful one with a very frightening militia, but he doesn't like the other major components. So you have the possibility here that this could fragment rather than stay together as one apparent -- it's not a bloc; they're separate.

JIM LEHRER: And do you agree with Juan Cole that he is seriously and sincerely desirous of the U.S. to get out of there?

JUDITH YAPHE: Oh, absolutely. But he doesn't say when. I think that he has -- he goes right up to the edge, but he doesn't really specify by this date, by this time. But that's something that all of these groups in Iraq has in common.

JIM LEHRER: Everybody says that now.

JUDITH YAPHE: That's right.

JIM LEHRER: OK, well, thank you both very much.

JUDITH YAPHE: You're welcome.