Anyone who believes that April has been the cruelest month of this Iraq war - 111 Americans killed with the total dead now at 718, hundreds upon hundreds of Iraqi civilians killed - should gird themselves for the reality that the worst, the very worst, the unimaginably awful, is still yet to come.

It is bad enough that this second Bush war in Iraq has yielded nothing of what was promised by George and his merry crew. There are no weapons of mass destruction, there was no connection between the deposed Hussein regime and al Qaeda, there was no connection between Hussein and September 11, there will be no democracy for Iraq, and the Iraqi people have most definitely not welcomed us with open arms.

Instead, Bush has mobilized anti-American sentiment to such a staggering degree that Shi'ite and Sunni, enemies for generations past counting, have united to fight us. The invasion and occupation has spurred an al Qaeda recruitment drive that has swelled the ranks of that organization. A lot of people are dead, American and British and Spanish and Polish and Iraqi alike. Nine Americans and 28 Iraqis were killed this weekend alone. The light at the end of this tunnel is an oncoming freight train.

That's not the worst part, however. The worst part is yet to come, in two cities called Falluja and Najaf. Americans paying attention to the spiral of violence in recent weeks will recognize those names, for they have been at the center of heavy combat since the month of April began. Bush administration officials, rocked back on their heels by the eruption of death there, were forced at one point to sue for a cease fire with the 'insurgents' they had supposedly defeated last May, when the mission was declared accomplished and the end of major combat operations was declared over during a photo-op on an aircraft carrier several time zones away from the violence.

The cease fire has failed, and American forces are at this moment surrounding Falluja and Najaf with the intention of invading these cities and routing the 'insurgents.' A showdown is coming, and nothing good will be made of it.

U.S. military planners have spent many years now studying about and training soldiers for the realities of urban combat. The city of Falluja should be the first chapter in the urban combat strategy binder titled "Worst Terrain Imaginable." The city has nearly 300,000 residents and is made up of a dizzying maze of narrow streets, wide boulevards and back alleys. Most of the apartments have porches that will serve Iraqi snipers and RPG-toting helicopter hunters well. Every neighborhood has a mosque, a school, markets and clinics which, if struck by an errant American bomb, will deliver horrible numbers of civilian casualties.

The politics of the looming Falluja incursion are another thing again. Hajim al-Hassani, of the Iraqi Islamic Party, sits on the American-compiled Iraqi Governing Council, but has little credibility among the people in Falluja. He is seen as not having been able to stop American forces from fighting in that city, and the Iraqi Islamic Party itself has been accused of collaboration with America. The mayor of Falluja, Mahmoud Ibrahim, is disliked by many of the city's residents. He informed officers of the American forces a few days ago that he had no control over Jolan, Hayal Askeri and Shuhada, three sections of the city which make up half its area. In other words, both representatives for this town are basically useless in any effort to call a halt to the attack.

The religious aspect is easily the most explosive element in this matter. Falluja is a Sunni town. Through the almost mystical bungling of the Bush administration, it has become tied to the holy city of Najaf, a Shi'ite stronghold. This city, like Falluja, has been surrounded by American forces and faces imminent attack. If an attack against Najaf is indeed undertaken, the consequences for Iraq, and indeed for the entire Middle East, will be unimaginable.

Najaf is the site of the tomb of Ali, the most important Shi'ite saint. It is a holy city, like Mecca and Medina, and is the symbolic capital for Shi'ites all around the world. If American forces attack Najaf, every Shi'ite on the planet will have a dog in the fight. Iran, a Shi'ite-controlled nation, may well become involved. Shi'ite religious leaders will issue fatwas demanding massive numbers of suicide attacks against Americans.

Do the math.

American forces attack Falluja, and become ensconced in a brutal street-to-street fight within the confines of that maze-like city. 300,000 civilians will be caught in the crossfire, and the resulting carnage will enflame the Iraqi people to a degree not yet seen. American forces will absorb brutal casualties. If the U.S. decides to avoid troop casualties by bombing Falluja in a repeat of Shock and Awe, the loss of civilian life will be beyond severe.

Simultaneously, American forces attack Najaf, a holy city central to the spiritual lives of millions of Shi'ites around the world. An explosion of rage will engulf the Middle East. Iran, which has something resembling a real army, could very well drive across the border to engage American forces that are already stretched. This war, already a ridiculous mess, will become an unmitigated catastrophe.

Anyone who thinks Iraq is a bad situation now should reserve judgment until the end of this week. George W. Bush and his crew have clearly forgotten the First Law of Holes: When you find yourself deep in a hole, stop digging. If this is what Bush meant when he talked about "changing the world" in his recent prime-time press conference, we are all in a great deal of trouble.

William Rivers Pitt is the senior editor and lead writer for truthout. He is a New York Times and international bestselling author of two books - 'War on Iraq: What Team Bush Doesn't Want You to Know' and 'The Greatest Sedition is Silence.'