In the summer of 2006, I came home from Iraq. I left a nation in chaos. Ethnic cleansing was in full swing. Sunni Iraqis were murdering Shia Iraqis by the truckload, and the Shia were doing the same to the Sunnis. Kurdish Iraqis wanted their own state, and were prepared to send their militia to war over control of Kirkuk and its oilfields. The Shia dominated government of Prime Minister Nouri al Maliki held power only by virtue of his party’s coalition with an erratic Muslim cleric and Iranian toady named Muqtada al Sadr.

It is now 5 1/2 years later, and the last American troops have come home from Iraq. What have these years brought us?

In the intervening period, about 2,000 coalition troops were killed in action, almost all of them American. Thousands more were wounded.

During this same period, the United States spent at least $250 billion, and perhaps as much as $914 billion on this war, although the financial accounting for Operation Iraqi Freedom has always been a subject of considerable debate.

To get some perspective on these numbers, $740 billion is the annual cost of Social Security, $840 billion is the annual cost of Medicare and Medicaid, and about $500 billion is the annual interest on the national debt. One may quibble about the numbers, but one thing is undeniable: since I came home, a lot of American blood and treasure has been spent in Iraq.

After coming home and retiring from the Army, I was invited to speak to a number of Rotary Clubs, churches, Exchange Clubs and other venues. I also wrote a number of opinion pieces, including in this newspaper, about the future of Iraq and what our policy should be there.

It was my view that our continued military occupation of Iraq would only delay the final reckoning. Absent an unlikely political accommodation among Iraq’s Sunni, Shia and Kurd factions, the best we could hope for was to suppress these conflicts until the American people ran out of money, patience, or both. Then, these conflicts would erupt again until they were decided by force of arms.

My views were not welcome in some quarters, and particularly coming from a senior Army intelligence officer who had recently served in Iraq.

Instead, conceived by retired Army Gen. Jack Keane of the American Enterprise Institute, and executed by Gen. David Petraeus, the Bush administration embarked on a "surge strategy." Another 40,000 American troops were dispatched to Iraq in the hope of pacifying the country and establishing an Iraq that was "peaceful, united, democratic and secure."

After a time, the level of violence abated. Whether this was due to the surge or due to other factors is a question that military historians will argue for decades to come.

Yet, the relevant question is whether the surge, and the additional 51/2 years between my return from Iraq and that last soldier’s return, justified the expenditure of 2,000 lives and $250 billion to $900+ billon of taxpayer dollars.

What has that investment of blood and treasure brought us?

Today, Iraq is a nation in chaos. Ethnic cleansing is in full swing. Sunni Iraqis are murdering Shia Iraqis by the truckload, and the Shia are doing the same to the Sunnis. Kurdish Iraqis want their own state, and are prepared to send their militia to war over control of Kirkuk and its oilfields. The Shia-dominated government of Prime Minister Nouri al-Maliki holds power only by virtue of his party’s coalition with an erratic Muslim cleric and Iranian toady named Muqtada Al Sadr.

In other words, that additional investment of blood and treasure has bought us absolutely nothing. Post-withdrawal Iraq may turn into an endless civil war, or a Mesopotamian version of Somalia, or a new police state with al-Maliki or some other Shia strongman in charge and beholden to Iran.

There is a lesson here for American presidents who have embarked on "surge" strategies in other ongoing conflicts, as well as those presidential candidates who would readily commit the nation to new military interventions.

Retired Col. Thomas D. Farrell, a Honolulu attorney, served as an Army intelligence officer in Iraq from June 2005 to May 2006. He wrote this commentary for the Star-Advertiser.