On one level, this is a wartime diary written by a literate brigade commander explaining how to lead 3,500 soldiers in the face of sudden, episodic violence. The reader will be exhausted following Col. Peter Mansoor through a year of 15-hour days, where his attention was divided between wartime operations and political interactions with Iraqis. At another level, this is a book that commanders should study, asking themselves: What would I have done if I had believed the overarching strategy was wrong? Throughout the book, Mansoor (now retired) wrestles with that question.

He brings a unique perspective to the issue. In 2003–04, he was an armored-brigade commander in Baghdad as the insurgency gathered momentum, and that is the focus of his book. He explains that the U.S. Army responded with a strategy of “offensive operations” — raids aimed at finding the insurgents, while the U.S. soldiers lived on bases separate from the people. In 2005–06, he returned to the States and was a principal author of the new Army field manual on counterinsurgency that strongly opposed the strategy of offensive operations. In 2007, he returned to Iraq as executive officer to Gen. David Petraeus, who advocated counterinsurgency and insisted that U.S. soldiers no longer live on bases separate from the people. So Mansoor was a participant in both strategies — offensive operations and counterinsurgency.

He begins his book by coming down firmly on the side of the Army’s 2007 strategy of counterinsurgency. “A military force,” he writes in the introduction, “must live with the people it would defend.” He thus sets up the basic problem to be discussed in his careful, readable book: the institutional resistance to changing course. Mansoor, the top academic graduate in his class from West Point, understood what needed to be done. Yet that was not what happened.

In July 2003, as the insurgency gathered momentum, Brig. Gen. Martin E. Dempsey (who rose to three stars in charge of the Central Command in the summer of 2008) ordered Mansoor “to consolidate our troops into battalion-sized bases.” This was the beginning of the notorious pullback into huge FOBs, or Forward Operating Bases, far removed from the population. Mansoor writes that he supported the decision: “in retrospect, probably the wrong call.” The pullback was followed by an order “to execute ‘offensive operations’ to destroy enemy forces. I [Mansoor] winced.”

His wince is understandable. U.S. forces were sallying forth in search-and-destroy operations against insurgents in civilian clothes whom they could rarely identify, then retreating back to their FOBs and conceding the neighborhoods to insurgent gangs. As a student of counterinsurgency, Mansoor understood the strategy of offensive operations was incorrect. As a brigade commander who was losing soldiers, he confronted the tension between counterinsurgency theory and practice. After a roadside bomb killed a lieutenant, Mansoor decided that “before we could win the hearts and minds of the Sunni residents in Adhamiya [District], we first had to earn their respect. . . . The gloves were about to come off.” But when taking off the gloves to conduct months of episodic, large-scale armored raids yielded scant payoff, Mansoor concluded that “we needed infantry in patrol bases spread among the population.”

What happened instead, in November 2003, was that Brigadier General Dempsey decided that (in Mansoor’s words) “the situation was stable enough to begin reducing the coalition presence in Baghdad” and sending back to Germany one-third of all armored vehicles. The goal in combating insurgencies was to deploy one soldier or policeman per 50 inhabitants in disputed areas — but in Baghdad, Mansoor noted a ratio of one U.S. soldier per 600 inhabitants, plus a smattering of untrained Iraqi soldiers and corrupt police. Mansoor objected to Dempsey’s order, to no avail. For the next four years, Adhamiya remained a stronghold for Sunni resistance in Baghdad.

Yet it took a while for the strategy’s failure to become evident. By the end of 2003, Mansoor observed, “Operation Iron Hammer made me optimistic about the security situation in central and northeast Baghdad.” Offensive operations seemed to have paid off. But the insurgency continued to advance, says Mansoor, because the Coalition Provisional Authority (CPA) under the leadership of Amb. L. Paul Bremer “failed to bring the real leaders of the Sunni community into negotiations, ensuring their continuing resistance.” Indeed, he castigates Bremer’s operation throughout the book as authoritarian, ignorant, arrogant, and downright dangerous to U.S. interests.

In April 2004, the wheels came off the military and political efforts in Iraq. President Bush approved an assault against the fractious Sunni city of Fallujah, then ordered a retreat when Bremer reported that the Iraqi officials advising him were threatening to resign. At the same time, Bremer had moved against the militia loyal to the renegade preacher Moqtada al-Sadr, who responded by rebelling. His militia in Sadr City took to the streets to battle American units. Far from being stable, Baghdad became the scene of heavy fighting, partially because, the author points out, “the 2nd Armored Cavalry Regiment, which had been unable to curb the expansion of Sadr’s militia, had just relinquished control of the area.”

The author and his command — the 1st Brigade of the 1st Armored Division — were rushed south to Karbala, where they heroically assaulted and disrupted Sadr’s militia. In July 2004, the 1st Brigade returned to its home base in Germany and received a richly deserved Presidential Unit Citation. But Mansoor was frustrated because, “in the end, the victory was largely squandered by decisions that allowed Moqtada al-Sadr to escape.”

Mansoor concludes the book by discussing insurgencies in the 21st century. It’s unsurprising that his conclusions reflect the thinking of his equally incisive boss, Gen. David Petraeus. As the justifiably proud commander of a battle-tested brigade, he concludes that “U.S. forces in Iraq in the winter of 2003–04 had created the conditions for political reconciliation and an end to the insurgency, provided CPA altered its strategic approach.” As a dispassionate analyst, however, he concludes that efforts in the war’s first year “to kill and capture insurgents led to a violent, real-life version of the carnival game ‘whack-a-mole.’”

So what’s the truth? Was the pullback strategy in Baghdad in 2003–04 a mistake, resulting in “whack-a-mole” — or a success, creating the right conditions to “end the insurgency”? Mansoor explains that at the end of 2003 there was a window of opportunity to reach out to the Sunnis, bring in their leaders, and preempt their support of burgeoning resistance groups. He points out, however, that Bremer’s operation slammed that window shut; and then the insurgency flared up. By late spring of 2004, Mansoor had concluded that “the withdrawal from our forward operating bases inside Baghdad was a huge mistake. . . . Had we remained positioned inside Baghdad to secure the Iraqi people and assist them in developing a new state, the sectarian cleansing that tore the fabric of Iraqi society two years later would not have occurred.” The author writes that he made “a weak entreaty” to Brig. Gen. Mark Hertling (now a division commander in Iraq) for the 1st Brigade to remain inside Baghdad, but to no avail. He attributes the mistake of withdrawing to bases to the “concern among senior leaders that coalition forces would overstay their welcome in Iraq’s cities, thereby turning liberation into occupation.”

This raises the question: How does the Army as an institution learn, especially at the top levels? This is not an academic question; the Army is the service in command in both Iraq and Afghanistan, having since 2003 held 17 out of 18 senior command slots. Four of the five CentCom commanders have been Army, as have been the four Multinational Commanders and five Corps commanders in Iraq, and the four senior commanders in Afghanistan. The responsibility for adapting at the top level thus falls principally on the Army.

As both a senior Army commander and a top-notch strategist, Mansoor has the keen insights, analytical rigor, and extensive contacts to probe the critical subject of how a massive institution changes strategy during war. Why did it take three years for the Army to change strategy in Iraq? The U.S. is about to change strategies in Afghanistan, now that General Petraeus is in charge of the Central Command. Why did it take six years in Afghanistan before a change was made? What are the mechanisms that ensure that change is carried out? Now a professor at Ohio State, Mansoor is the right man to address those questions in a follow-on book.