Iraq is engaged in a full-fledged civil war. For those remaining defenders of the U.S. occupation of Iraq, who argue that the United States needs to stay put in order to prevent civil war, it’s too late. It’s here, in all of its brutality and ugliness.

The violence is not only engulfing Baghdad—home to approximately one-fifth of Iraq’s population—but Basra, Iraq’s second city and its only port.  In the north, there is violence in Kirkuk, in what has been, until now, the relatively unscathed heartland of the Shiite south, as well.

What is unfolding in Iraq is a staggering tragedy. An entire nation is dying, right in front of us. And the worst part of it is: It may be too late to do anything to stop it.

The toll among ordinary Iraqis is immeasurable. Iraqis are dying in ones and twos, in a wave of rampant murders, kidnappings, and assassinations throughout the country. They are dying in fives and tens, through roadside bombs, car bombs, and sectarian violence. And they are dying in large numbers, in scores, as organized armies carry out atrocity after atrocity in brazen, public attacks.

A United Nations report released this week says that the death toll among Iraqi civilians since January 2006 is 14,338. The number killed has been rising steadily each month, from 1,778 in January to 3,149 in June. That report significantly understates the actual totals. The U.N. relied on official data reported by the Iraqi government, which is prone to omit some of the dead. But in any case the situation in Iraq is so chaotic that it is impossible to count their numbers, especially in far-flung provinces. Still, the U.N.’s figures far surpassed previous estimates of casualties from any source.

What’s shocking—especially if you’ve been paying more attention to the destruction of Lebanon by the Israeli armed forces and missed it—is that things in Iraq has gotten qualitatively worse in July. In June, Iraqis died at the rate of nearly 1,000 per week. In July, we can only speculate—but it’s not impossible that the toll is at least twice that, 2,000 per week. The word genocide comes to mind.

On July 9, in a first, scores of uniformed Shiite militiamen invaded and cut off a Sunni neighborhood in a Baghdad suburb and carried out a bloody pogrom. The heavily armed Shiite gunmen systematically singled out Sunni men, woman and children and shot them in cold blood, sometimes entering homes and murdering entire families in a face-to-face orgy of slaughter that lasted for hours, leaving as many as 60 dead. Since then, violence in Iraq has spiraled out of all control, in a wave of bombings and killing beyond anything that the country has seen since 2003—worse, even, than the outburst that followed the Feb. 22 bombing of the Golden Dome mosque in Samarra. Since July 9, freelance gunmen, militias, and paramilitary armies have attacked buses and minivans, killing all aboard, and they have carried out mass kidnappings of scores of Iraqis at a time. Some of the violence seems literally senseless, as this July 13 report reveals:

Security forces said the bodies of 20 bus drivers kidnapped earlier in the day from a bus station in Miqdadiya north of Baghdad were found in a village to the north. They had been blindfolded, bound and shot in the back of the head. Major General Ghassan al-Bawi, the police chief of Diyala province, said the kidnappings aimed to undermine a recent reconciliation accord agreed by Sunni and Shiite tribes in the area. He said 10 of the drivers were Sunni, the rest Shiite…

Among the most horrific incidents, on July 17 Sunni gunmen invaded and surrounded a largely Shiite crowd in a marketplace in the town of Mahmudiya, south of Baghdad, and using assault rifles, machine guns, and rocket propelled grenades, killed 48 people in broad daylight—an attack described as revenge for the July 9 massacre. The next day, a suicide bomber in a truck killed 59 people in Kufa, a Shiite city in south central Iraq.

In nearly all of these cases, Iraqi security forces were either powerless to intervene or chose not to do so. In some cases, the perpetrators themselves are believed to have been members of the Iraqi police or Interior Ministry forces. And in Mahmudiya, according to some reports, U.S. forces stood by and decided not to act, and a U.S. commander told the press that the United States will not intervene in Iraq’s civil war strife. So much for the U.S. presence in Iraq preventing civil war.

As in Beirut, Lebanon, during the 1975-1990 civil war that killed perhaps 100,000 people, lines are being drawn down the middle of Iraqi cities, signaling that the rough outlines of civil war territories are being staked out. London’s Daily Telegraph reported this week:

Highway 60 has become one of the bloodiest fronts in the war between Sunni and Shia. Known to its frightened inhabitants as the "street of death," the road in the south-east of the capital is a symbol of the sectarian violence that is pushing the country ever closer to the abyss.

In a stunning Washington Post article, "Neighbors Are Killing Neighbors," recounting just part of the slaughter in Baghdad that left 628 killed in a few days, Joshua Partlow and Naseer Nouri reported:

After more than a week of some of the most vicious sectarian violence of the war, Baghdad is a skeleton of a city: Many of its shops are shuttered, its streets drained of people. … Across large swaths of territory south and west of the Tigris River—Baghdad neighborhoods such as al-Jihad, Amiriyah, Ghazaliyah and Dora—residents who have not fled spent days virtually imprisoned by the military checkpoints and street fighting between residents and marauding militiamen.

And it’s not just Baghdad and surrounding areas. Scattered reports from cities like Kirkuk, Mosul and Basra indicate the violence is rapidly escalating there, too. In Basra—previously an oasis of calm compared to Baghdad—British forces are engaged in running battles with rogue Shiite militias.

The blame for this carnage must be laid squarely at the feet of George W. Bush. The U.S. invasion of Iraq was ordered against the advice of the CIA, the State Department and most U.S. military officers, and in defiance of the United Nations, America’s allies, and the Arab world. The United States attacked and destroyed a nation that had never attacked the United States, which had no weapons of mass destruction and which had no connection to al-Qaida.

Despite grumbling this week from Republicans in Congress that the war has gone off the tracks, despite warnings from serious-minded analysts such as Tony Cordesman of the Center for Strategic and International Studies ("These trends strongly argue that the Iraqi government and United States are now losing, not winning."), there is no sign that the Bush administration is willing to change course in Iraq.

Instead, when U.S. Energy Secretary Samuel Bodman met with Iraq’s oil and energy ministers in Baghdad this week, The New York Times reported that he had "a rosy view of progress" since his last visit in 2003:

 "The situation seems far more stable than when I was here two or three years ago," he said in an interview in the fortified Green Zone. "The security seems better, people are more relaxed. There is an optimism, at least among the people I talked to."