The intelligence people are picking up chatter regarding a major al Qaeda attack in Iraq, coordinating a large number of fighters to pull something off like the Abu Greib operation last year, possible against Parliament or the U.S. Embassy. It doesn't have to succeed, just make a big splash in the media. Overall, al Qaeda attacks are way down, and the terrorist organization is taking a beating. All they can hope for now is some media victories.
Many Department of Defense and CENTCOM analysts are putting the chances of an Iraqi "civil war" at 60-70 percent. However, this civil war would be more like Bosnia in the early 1990s. That is, the majority of Iraqis (Kurds and Shia Arabs) trying to kill or drive out the minority (Sunni Arabs). The Sunni Arabs are well aware of this, and more of them are openly lining up with the government. An example is the recent open declaration of war against al Qaeda by several major Sunni Arab tribes. The al Nuaim, Ibrahim al Nuaimi, Jubur tribes have all declared war on al Qaeda, and they all did so because al Qaeda recently assassinated leaders of those tribes. Al Qaeda has seen its relations with the Sunni Arab tribes go downhill over the last two years. Killing tribal leaders is the last, desperate, attempt to terrorize the tribes. This has failed.
The main cause of this rift was the al Qaeda obsession with causing a "war" between the Sunni Arabs and the majority of Iraqis (Shia Arabs and Kurds). The problem here is that the al Qaeda strategy is based on several myths. The biggest myth, which many Iraqi Sunni Arabs believe, is that Sunni Arabs are actually the majority of the population in Iraq. Most Sunni Arab leaders know better, but these leaders also believe that it would be best for Iraq if the Sunni Arabs were back in control. This is what al Qaeda has always believed. But the reality is that the Sunni Arabs are only 20 percent of the population, and the majority Shia Arabs and Kurds now have more guns, and they have the American soldiers backing them. The Sunni Arab tribal leaders believe the al Qaeda leadership is insane, and willing to lead the Iraqi Sunni Arabs into a suicidal battle. Shia Arabs and Kurds make no secret of their belief that Iraq would be a better place if all the Sunni Arabs were gone.
The popular (with American generals) commander of the Iraqi 6th Infantry Division was apparently assassinated on March 6th. While out, with his considerable bodyguard, to investigate a situation, he was shot once in the head as he was getting out of his armored vehicle and putting his helmet on. Major General Mubdar Hatim Hazya al Duleimi was a Sunni Arab, who got his job despite the resistance of the Shia Arabs who run the Defense Ministry. The Shia Arabs wanted a Shia Arab to command the 6th division, while the Americans wanted the most competent officer (al Duleimi) in charge. The Shia Arabs are thinking in terms of politics (as in the traditional Iraqi preference for military coups), while the Americans wanted a general who would bring peace to the Baghdad neighborhoods the 6th division was responsible for. Al Duleimi's death is under investigation.
Shia Iran has made no secret of its support for the Shia Arabs in Iran. This support includes money, advisors and, apparently, armed members of Iranian religious militias (the Revolutionary Guards). Iran would also like to expel the Sunni Arabs from Iraq. What bothers the other Arab nations in the Persian Gulf is that Iran could get away with this, if the Americans were not in the way. It's been over a thousand years since an Arab army defeated an Iranian one. Saddam's ability to fight the Iranians to a standstill (and a draw) in the 1980s, is considered a great Arab victory. But this victory was only accomplished with an enormous amount of financial aid, and some assistance from Western nations (especially France and Germany) that wanted to safeguard their oil supplies. Without that continued support, the Persian Gulf would be entirely Persian (as the Iranians used to call themselves until the 1930s).
Iran cannot openly confront their neighbors now, but if they have nuclear weapons they can. Such a threat may not work, but when nukes are involved, people get a lot more cautious. With, or without, nukes, Iran is always a threat to the region, because Iran has, for thousands of years, been the dominant power. That is no longer the case, and has not been since the Turks came in four centuries ago. In the last century, the West has replaced the Turks. But the Iranians still remember the good old days fondly, and many want to restore former glory. Nuclear weapons could do that, Arabs in general, and Sunni Arabs in particular, are terrified of that happening.