The surge is starting to open rifts. None of the players within each group seem sure yet how to respond to it, so they’re taking advantage of each other’s momentary uncertainty to jockey for power.

1. Shiites vs. Shiites. Why has Sadr played ball with the security plan so far? Because, the Times speculates, it lets him wound two birds with one stone — his Iranian sponsors and his disloyal underlings, each of whom has direct links to the other and could threaten his power if he outlives his usefulness to them. So he’s sending to message to Tehran by dropping a dime on the rogue members:

In perhaps his boldest move yet, Mr. Sadr has assisted the joint Iraqi-American campaign against parts of his militia, signaling whom to arrest and telling others to flee, said two Mahdi commanders and a Shiite politician in Baghdad. On his own, they said, Mr. Sadr has “frozen” more than 40 commanders, including about 20 with links to Iran…

They said the cleric allowed the arrests of members of his own militia, or suspended them himself, because evidence showed that they had not obeyed his orders and because he wanted to show Iran, American officials and his militia that he was a strong leader who must be respected and feared…

“Iran puts Moktada al-Sadr between two pressing sides,” he said. “On one hand, they are helping him and they have the ability to take that away. At the same time, they’re undermining him by helping people below him.”

According to Sadr aides and Mahdi commanders, Mr. Sadr’s recent purges aim to put Iran on notice that he is in charge and independent. They said he also wanted to remind members of his militia that he would use every available tool, including Iraqi and American troops, to maintain control of the militia, the source of any political power he wields.

Sadr’s problem in lying low is that he’s not the only game in town. Some of the Shiite leaders who spoke to the Times claim that SCIRI gets more help from Iran than he does. If the surge can’t protect Shiites from Sunni jihadis then Iran may try to capitalize by getting SCIRI to fill the security vacuum in hopes of shifting public loyalties to a more controllable Shiite group and freezing Sadr out. Perhaps sensing that, Sadr released an angry statement after today’s university bombing denouncing the security plan and clearing some rhetorical space for him to increase the Mahdi Army’s presence on the streets again.

A Shiite MP interviewed by the Times claims Iran is also funding some Sunni groups for essentially the same reason corporations donate to both Republicans and Democrats. That makes sense — the more attacks there are on Shiites, the more the U.S. suffers and the more attractive Iran’s Shiite proxies appear as a security alternative.

Iraq’s NSA insists that Iran’s meddling in the country has now ceased, but of course, he’s the same Sadrist tool who attended Saddam’s funeral, insisted in phone calls to Fox News and CNN that it went off without a hitch, then denounced it as a disgrace when the cell phone video hit the Internet.

2. Sunni vs. Sunni. The Baghdad surge gets all the headlines, but 4,000 Marines are on their way to Anbar to clear out Al Qaeda’s influence in the west. The battle for Ramadi, ground zero of the Sunni insurgency, is on tap for April. Petraeus is trying to bring some of Saddam’s Baathist ex-generals on board for the fight and stands a chance of doing so, thanks to the fact that many of the Sunnis whom AQ is supposed to be “protecting” have come to roundly, sorely despise them. Which explains why we’re now seeing things like this:

At least 37 Iraqis were killed Saturday in a highly unusual insurgent bomb attack against Sunni Arabs as they were leaving a mosque.

A preacher at the Sahaba mosque in Habbaniya, 40 miles west of Baghdad, had delivered a blistering sermon a day earlier condemning Al Qaeda activities in Iraq, an official in the town said…

Shiite Muslims are the main Iraqi targets of the Sunni-led insurgency. But police and residents in the Sunni Muslim-dominated area said the people had largely aligned against Al Qaeda militants operating in the region. They said most of the young men in the village, between Fallouja and Ramadi, were employed in the police and the army — unusual for Al Anbar province, long a hotbed of insurgent activities.

The AP has a long, worthy piece about the escalating “fratricide” between pro- and anti-jihadi Sunnis, but what they’re really describing is Anbar’s version of a civil war. There’s dissension in the ranks of the jihadis themselves, too, a subject I touched on Friday. The Sunnis’ problem is that the jihadis are the closest thing they’ve got to an army, so if they move against them and crush them, they end up defenseless against the Sadrists in and out of the government (unless, of course, the Saudis intervene).

The Shiites can count on the protection of the police, who are led by Shiites, and on their miliitas, including the powerful Mahdi Army of radical cleric Muqtada al-Sadr. The Kurds of northern Iraq are protected by their traditional mountain guerrillas, called the peshmerga.

Many Sunnis — who were favored under Saddam — now feel vulnerable without a homegrown armed faction on their side. A “senior defense source” told the Times of London that many of the sheikhs in Ramadi have already lined up with the U.S. in preparation for the coming attack

“Groups like al-Qaida in Iraq exploit these fears among Sunnis and tell them things like, ‘We are here to protect you,'” said Alani, the security analyst.

If Petraeus can bring some of the Baathists in, maybe that’ll galvanize the locals. According to a “senior defense source” who spoke to the Times of London, many of the sheikhs in Ramadi are already lined up with the U.S. in preparations for the coming assault on the city.

Should be a piece of cake. Like Murtha says, the Sunnis can purge AQ anytime they want, at the drop of a hat, no?

3. Democrat vs. Democrat. And speaking of Spanky, behold as his klutzy egomania alienates the Blue Dogs and puts the slow bleed in mortal jeopardy:

The story of Murtha’s star-crossed plan illustrates the Democratic Party’s deep divisions over the Iraq war and how the new House majority has yet to establish firm control over Congress. From the beginning, Murtha acted on his own to craft a complicated legislative strategy on the war, without consulting fellow Democrats. When he chose to roll out the details on a liberal, antiwar Web site on Feb. 15, he caught even Pelosi by surprise while infuriating Democrats from conservative districts…

“He stepped all over Speaker Pelosi’s message of support for the troops,” said Rep. Jim Cooper (Tenn.). “That was not team play, to put it mildly.”

Even after that Web appearance, some senior Democratic aides say Murtha might well have been able to save his plan if he had quickly laid it out before the Democratic caucus and marshaled Democratic leaders behind a defense. Instead, the House recessed for a week, Murtha disappeared from the media, and Democratic leaders were silent, saying they could not discuss Iraq legislation because no real plan existed.

In the face of an unanswered Republican assault, the Democratic rank-and-file cracked — on the left and the right.

Tough spot for Pelosi, who’s not only caught here in the schism between centrist Dems and the anti-war left but who may have to oppose Murtha on his pet issue. She backed him for majority leader when he didn’t have the votes and embarrassed herself in the process; that’s how deep her loyalty to him runs. Having to defang the slow bleed would be painful for her, I’m sure. And incredibly amusing for us.

I leave you with the words of another Democrat who’s not actually a Democrat anymore, thanks to that schism I just mentioned: “[W]e must not make another terrible mistake now. Many of the worst errors in Iraq arose precisely because the Bush administration best-cased what would happen after Saddam was overthrown. Now many opponents of the war are making the very same best-case mistake–assuming we can pull back in the midst of a critical battle with impunity, even arguing that our retreat will reduce the terrorism and sectarian violence in Iraq.”

Exit question: Is the GOP headed for a civil war itself?