[Wolf Blitzer, Cnn Anchor:] Happening now, breaking news we're following, a startling exit from Iraq by a powerful anti-American force. Details are just coming in. This is a story with enormous ramifications for the U.S. military mission in Iraq. We're going to bring you the latest in a moment. Also, America's top general appears at odds with the Bush administration. At issue, is the Iranian government arming insurgents in Iraq? You'll want to hear the tough questions that prompted a cold stare over at the White House. Also this hour, the threat of nuclear war would Israel attack Iran to keep it from getting the bomb? Tonight we'll map out a chilling scenario. I'm Wolf Blitzer. You're in THE SITUATION ROOM. We begin with breaking news out of Iraq. Muqtada al-Sadr, the powerful anti-America Shiite cleric has now left the country for Iran. Our senior Pentagon correspondent, Jamie McIntyre, is standing by, but let's go to our White House correspondent, Suzanne Malveaux. She's getting the latest information. Suzanne, this is a story with enormous ramifications, as I said, given the forces Muqtada al-Sadr controls in Iraq, what are you learning?
[Suzanne Malveaux, Cnn White House Correspondent:] Well absolutely, Wolf. This is very significant. I have spoken with two senior administration officials this evening who have confirmed that Muqtada al-Sadr, this powerful Shiite, anti-American Shiite, the cleric, left Iraq two to three weeks ago or so and headed straight for Tehran, Iran. That's where they still believe he is now and they say this is extremely significant. The reason why, first and foremost, they say that there are some signs that perhaps the Mehdi Army, some extremists within his own group, are fracturing and that there are some divisions that have taken place, which would weaken Sadr as well as the Mehdi Army. The second thing, of course, here is that it has been very difficult for Iraq's Prime Minister Nuri al-Maliki to crack down on these militias, particularly those from Sadr's group. He's been reluctant to do so in the past, although there have been signs that he has gotten tougher on that group. With Sadr out of the picture, this may mean of course that he has less to worry about. The other cautionary note here, Wolf, is that perhaps Nuri al-Maliki has more to worry about. Those extremist elements that have divided, that have fractured from Sadr, but senior administration officials do believe it's a significant development here, that perhaps in light of this anticipated military surge, that Sadr left out of fear for his own safety, and that may happen with other leaders as well Wolf.
[Blitzer:] This is a guy who has been wanted by the U.S. military almost from the beginning of the U.S.-led invasion. The first commanding general, Ricardo Sanchez said Muqtada al-Sadr had American blood on his hands. He ordered his Mehdi Army to kill Americans. He was wanted, in fact, dead or alive, although that lately has changed as he's formed a political alliance with the current prime minister of Iraq, Nuri al-Maliki. My immediate suspicion, Suzanne, was that as soon as I heard he had fled to Iran, he clearly feared the U.S. now is going to get tough with him, either arrest him or kill him.
[Malveaux:] Well you're absolutely right, Wolf. Because senior administration officials I have spoken to say that is right. That he in fact is fearing for his life, for his safety. That he's anticipating this military surge, this crackdown, if you will, on the militias and so he essentially took off. That this is a very good development because even before this military surge has really come to fruition, there's already some results here that perhaps they are intimidating Sadr, this very powerful leader. And as you said, Wolf, really Maliki's very power depends on Sadr, depends on those that are in the parliament, depends on the party that put him there, depends on those royalties with fellow Shiites. There's a real close relationship, a tie between these two, and perhaps seeing Sadr in Iran, out of fear, leaving the country, it makes Maliki clears the way for him to become a much more powerful figure within his own government Wolf.
[Blitzer:] Stand by Suzanne. I want to bring in our senior Pentagon correspondent Jamie McIntyre. Jamie, you're watching all of this and you're looking at the implications, what it means for the U.S. military. What goes through your mind?
[Jamie Mcintyre, Cnn Sr. Pentagon Correspondent:] Well Wolf it's clearly significant, but the question is what is the significance. You know you might point out that although Muqtada al-Sadr has left Iraq, according to these reports, he could also come back. And the U.S. military has been anticipating all along that as a result of this Baghdad security plan, that the likely response from some of the elements that they considered troublesome, including Muqtada al-Sadr's Mehdi Army, would be to simply lie low for a time, perhaps months, perhaps even more than that time. So it's not clear at all how much al-Sadr's leaving diminishes his influence. Is he still running part of his organization from Iran? Is he planning to come back? Is he planning to stay? Just stay out of the country for a while until he sees how things shake out? Clearly, he was concerned about, you would think, what was going to happen with this crackdown. And don't forget, this was led by Iraqi troops, Iraqi government troops who are not totally under the control of the United States and may not even have shown as much discipline. So it could have been a factor there, but at this point, I think it's really difficult to say exactly how this is going to shake out and what it's going to mean long term for security in Baghdad.
[Blitzer:] And as we welcome our international viewers watching us on CNN International to follow this breaking news, I just want to recap right now, Muqtada al-Sadr, CNN has confirmed, has fled Iraq for Iran, unclear why. About two, three weeks ago, Suzanne Malveaux, that's the information you're getting from your sources?
[Malveaux:] Well that's right. Senior administration officials say it was within that timeframe, two or three weeks ago, that that is when he decided he would flee Iraq and go to Iran. And as you know of course much has been made over the last couple of months or so about the president's new plan, this surge of military in the region of Iraqi forces as well as U.S. forces. The president and other senior administration officials talking about the progress they have seen those Iraqi brigades arriving in Baghdad. That they are positioning and making their way over to begin this military effort, so they believe that this is in response to that surge that anticipated surge.
[Blitzer:] Jamie McIntyre, the suggestion would be that the U.S. military about to get tough with the Mehdi Army, the Shiite militia controlled by Muqtada al-Sadr. But is the Iraqi army under the control of the prime minister, Nuri al-Maliki, who has political ties to Muqtada al-Sadr, is the Iraqi army ready to do the same, go into Sadr City, go into those areas that the Mehdi Army controls and get tough with this force?
[Mcintyre:] Well that was the big question, Wolf, as this new security plan kicked off, just how much commitment there was there. We saw some signs that the Iraqi government was willing to get tough. They did round up some people who are aligned with Muqtada al-Sadr and take them into custody. And it may have been the case that al-Sadr himself began to feel the heat and begin to think that maybe they were closing in on him. You know there was a big question because Nuri al-Maliki's entire ruling power there really sort of rested on having some kind of relationship with Muqtada al-Sadr. So there's a big question about to what extent he would really be able to go after him. And again, it's hard to read too much into this without knowing all of the facts going on behind his motivation, but it would seem to be an indication that the al-Maliki government is carrying through its threat to tackle all forces in Baghdad that would threaten security.
[Blitzer:] It does come at a time when the U.S. relationship with Iran, Jamie, is already complex and fraught with danger. If he has sanctuary in Iran some place at a time when U.S. military officials are accusing Iran of sending in very sophisticated explosives to kill Americans that further potentially could exacerbate this tension.
[Mcintyre:] Well you know sanctuary might be too strong a word in this case. We don't know really what his status is in Iran. And again, it's possible that at some future point he might want to come back. But you're right; the tensions with Iran are pretty high. And at this point, it makes it this is another situation where because we're not clear if this will be a net positive or a net detriment to the effort in Baghdad, it's hard to say whether this is something that the U.S. would welcome or not.
[Blitzer:] All right. Jamie McIntyre, Suzanne Malveaux, both of you stand by. I know you're working your sources on this developing story, the breaking news that we're getting that Muqtada al-Sadr, this anti-American Shiite cleric in Iraq has now fled to Iran. We're also going to be checking in with our Michael Ware. He's in Baghdad. We'll get the latest from there. Lots of news happening right now unclear the ramifications, the implications of precisely what this means, as Jamie McIntyre was suggesting. Let's go to Jack Cafferty. He's in New York. I'm not exactly clear what it means myself, but I want to learn more about this, Jack.
[Jack Cafferty, Cnn Anchor:] I'd like to know how he got out of Baghdad. Wasn't the entire United States military and all of the Iraqi police and security and military forces looking for this guy?
[Blitzer:] A lot of people were looking for him, but he had an enormous amount of protection from the Iraqi government of Nuri al- Maliki. Remember the guys he controls in the Iraqi parliament were enough...
[Cafferty:] No, I understand.
[Blitzer:] ... to give Nuri al-Maliki the job.
[Cafferty:] Yes, I just, you know with that many soldiers looking for him, and supposedly our intelligence being above average after four years in the theater over there, you wonder why somebody didn't have a little closer eye on this guy's whereabouts. I guess we'll find out more in the hours and days ahead. Meantime, back to domestic politics the 2008 presidential race already too much, too soon, amen the amen is mine. The rest of it is senior White House adviser Karl Rove saying that the election for 2008 is gearing up so early with candidates focusing on tactics and fundraising and publicity that they could well face a backlash from the voters. His remarks came in an interview with "The Politico". He said quote, "I think it's going to mean that people develop a persona earlier and wear out their welcome earlier than they would. I think there's going to come some point this year where people are basically going to say I'm largely disinterested in the contest" unquote. Interesting comments from a man who arguably knows a few things about how to win elections Rove notes that in 1998 after George Bush won re-election as Texas governor, he had a quiet and productive period in which to start shaping a message for his White House run. Rove contrasts that to now when the candidates are being forced into the field much earlier. We're doing some of the forcing, by the way. He also says the candidates will have to spend more time raising money because there's more time to spend money. So the question is this. What does it mean if Karl Rove thinks the '08 presidential race is gearing up too soon? E-mail your thoughts on that to CaffertyFile@CNN.com or go to CNN.comCaffertyFile. I think that the media is a little bit complicit in this early burst out of the starting gate, don't you, Wolf?
[Blitzer:] I think we're yes, I agree with you, Jack. I think we're covering it as we should. We have a responsibility to make sure our viewers know what's going on and it's an open race right now, a lot of candidates on the Republican side, a lot of candidates on the Democratic side, and we're doing our job, Jack.
[Cafferty:] There you go.
[Blitzer:] OK Jack Cafferty in New York. He's going to be coming up shortly. Also coming up, a tense exchange between the White House press secretary and one of our reporters. Listen to this.
[Unidentified Male:] Calm down. I know you're excited. Your voice is rising. Your pace is increasing. I'm telling you that... I'm telling you... He is saying this. I'm not.
[Blitzer:] It involved the question of credibility regarding the Bush administration's explosive claims about Iran. We're going to tell you just what caused that back and forth, and Ed Henry is standing by live. Also, he's his former boss and still a long-term friend, but will Vice President Dick Cheney take the stand to try to help defend his former chief of staff? There's a surprise development in the CIA leak trial of Lewis "Scooter" Libby and we'll tell you what happened today. And more on our breaking news that we're following. Muqtada al- Sadr, the top anti-American radical Shiite cleric in Iraq heads to Iran. There are enormous security and political implications. We're going to go to Baghdad and speak with our Michael Ware and get the latest. Stay with us. You're in THE SITUATION ROOM.