US officials warned for months that violence could rise in the weeks before the planned June 30 turnover of sovereignty to an interim Iraqi government, as rival sectarian and political groups angled for power and extremists tried to disturb the installation of functioning institutions.
But what is sweeping over Iraq is different from anything the US had anticipated, experts say, both in intensity and in terms of who is doing the fighting - which increasingly appears to be a possible unifying of radical Sunnis and dispossessed Shiite factions.
As fighting blazes in various parts of Iraq and increasingly involves formerly quiescent groups, war has in fact roared back. With prospects for more violent conflicts eroding the envisioned scenario of Iraq's stabilization and orderly transition, a host of new political and military risks are cropping up for the Bush administration.
"This is way beyond the scope of anything anybody who was talking about [an upsurge in violence] expected," says Patrick Lang, a retired Defense Intelligence Agency officer who specialized in the Middle East.
"We have a war going on in Fallujah," a city in the heart of the so-called Sunni Triangle, "with armor and helicopters and house-to-house fighting. We have the Shiite [cleric Moqtada al-] Sadr battling us from what looks like a growing number of locations, and you have the rest of the [Shiite] population watching with interest to see how this goes," Mr. Lang says. "This is a large-scale problem going on."
Perhaps too accustomed to the idea that Iraq had entered a tense but stabilizing postwar period, Americans may need to adjust that thinking to envision something closer to warfare, with continuing risks to US soldiers and a calendar with political and religious dates that will invite political violence, some experts say.
"It's been clear for quite some time that we face the risk of episodic violence and attacks at least until a newly elected government is to take over" by January 2005, says Anthony Cordesman, a former Defense Department official and Middle East expert now at the Center for Strategic and International Studies in Washington.
Saying that the US faces at least another year of war in Iraq, Mr. Cordesman says the violence that the US did not anticipate has forced the Bush administration and the military to replace plans for months of expected peaceful occupation with prospects for years of low-level conflict.
Even with the unexpected turn in Iraq, however, hardly anyone, on either side of the political aisle or among officials and experts, is talking about pulling out - largely because doing so would be even more costly and dangerous for American interests.
The White House continues to insist, as President Bush did Tuesday, that the US will "stay the course."
Not only would abandoning Iraq now increase the threat of civil war and breakup of a strategic country in the Middle East. But ceding to chaos would also raise global doubts about American resolve, and would send a signal to sectarian groups in Iraq and to Islamic extremists throughout the region that the US can be worn down and chased away.
"They've got a tiger by the tail, and they can't let it go easily, because it will bite them," says William Durch, a security and peacekeeping expert at the Stimson Center in Washington.
And one of the "bites" the US could face, should it show doubt about its mission, would be from extremists and other anti-Western elements in the region, some say. "The problem now that we've got ourselves in this situation is that if we show weakness," says Lang, "the most backward elements of those societies are going to be energized."
One result is that some US officials are talking more about the potential need to increase troops on the ground rather than drawing them down.
Sen. John McCain (R) of Arizona was on morning TV Wednesday, reminding Americans that he has been calling for additional troops in Iraq for six months. Saying national security is on the line in Iraq, Senator McCain says that unlike the engagement in Somalia, which the US walked away from in 1993, "We cannot afford to lose this."
But other political leaders say the solution is not to increase the number of troops - which could further inflame anti-American sentiments - but to increase international participation in Iraq.
"Pouring more US troops into Iraq is not the path to extricate ourselves from that country," said Sen. Robert Byrd (D) of West Virginia in a Senate speech Wednesday. "We need the support and the endorsement of both the United Nations and Iraq's neighbors to truly internationalize the Iraq occupation and take US soldiers out of the cross hairs of angry Iraqis."
Of course, the surge in violence in Iraq is still fresh and the picture is still unclear as to whether hints of a coming together of radical and frustrated Sunnis and Shiites will last. Nevertheless, new doubts are being raised about the ability to keep to the June 30 date for turning over sovereignty.
But in fact little of substance is likely to change on what is above all a symbolic date, some analysts say, and focusing on it may only be inviting more expectations - and more trouble. "June 30 is no seminal date at which some dramatic change will take place," says CSIS's Cordesman.
The other large elephant in the room influencing what happens in Iraq is the US presidential election. Iraq's power players are already toying with that date, experts say - while weighing the reality that an abrupt shift in US policy would only amplify the country's security vacuum and invite further chaos. "The Iraqis have political leverage over us because of our electoral calendar," says Mr. Durch, "but at the same time they need us, and will continue to need us for a while."