As the epigraph for his new book on the politics of America’s intervention in Iraq, George Packer has chosen a verse by the Arab nationalist poet Nizar Qabbani: “Dive into the sea, or stay away.” The poet’s charge aptly captures the thesis of The Assassins’ Gate: a great enterprise requires unequivocal commitment; to act half-heartedly is worse than not acting at all.

From the day it began planning to invade Iraq, according to Packer, a staff writer at the New Yorker, the Bush administration violated this dictum. “Swaddled in abstract ideas, convinced of their own righteousness, incapable of self-criticism, indifferent to accountability,” the senior officials who conceived the Iraq war (and the ideologues who egged them on) underestimated the magnitude of the task they were so eager for the United States to take on. As a consequence, this war of choice—which Packer, situating himself among the “ambivalently prowar liberals” hoping to free Iraq from the yoke of brutal dictatorship, had supported—evolved into a bloody and intractable mess.

Packer fixes the blame for this outcome squarely at the top. Among senior U.S. national security officials, the well-being of the Iraqi people figured at best as an afterthought. For Bush and Cheney, with their “mystical confidence in American military power,” for Donald Rumsfeld, Paul Wolfowitz, and Douglas Feith at the Pentagon, and for General Tommy Franks commanding U.S. Central Command, the invasion itself was the object of the exercise. The idea was to show that the United States after 9/11 had cast off old inhibitions regarding the use of armed force.

For that purpose, Saddam Hussein, a nemesis of long standing with a well-established reputation for making mischief, offered a convenient target. Counting on a crisp display of military superiority to overawe and therefore intimidate other existing or potential adversaries, those in positions of authority discounted the possibility that planting an American army in Baghdad might give rise to its own nasty complications. As an unnamed Defense Department official quoted by Packer remarked, “if you are Feith or if you are Wolfowitz, your primary concern is to achieve the war.”

Here Packer examines the human consequences of that achievement, looking “past the abstractions” to assess the war’s impact on the lives of ordinary Iraqis and Americans. He does this by telling their stories. The result is never less than interesting and is frequently compelling. Taken as a whole, The Assassins’ Gate has a shapeless quality, with Packer meandering from one scene to the next and occasionally doubling back again. Yet the stories themselves are powerfully illuminating.

A skillful reporter with a fine eye for anecdote and detail, Packer has a capacity for empathy that extends to just about everyone apart from oily con men like Ahmad Chalabi and neoconservatives like the hapless Feith (whom he repeatedly fingers as a lackey of the Likud Party). His Iraqi protagonists include contrite former Baathists and former prisoners of the Baath regime, footloose young men obsessing about sex, and ex-soldiers angling for entrée into the new political order. Packer introduces the reader to a dreamy dissident whose return from exile doesn’t quite work out as planned, to a Kurdish Jew eying an escape to Israel, and to an endearing teenage girl consumed by a yearning to experience Western-style freedom. He profiles the pathologist charged with carving up the corpses found littering the streets of liberated Baghdad and a psychiatrist obsessed with a harebrained scheme to redeem his countrymen by founding the “Gilgamish Center for Creative Thinking.”

On the American side, Packer’s subjects are perhaps less colorful, but they are hardly less interesting. His cast of characters features industrious, if largely clueless, officials giving their all to the dysfunctional Coalition Provisional Authority, within which, he writes, “the less one knew about Iraq, the more influence one had.” It includes idealistic GIs improvising responses to the baffling problems of the occupation, with little guidance and less assistance from higher authority. Most affectingly, it dwells on a bereaved Iowan struggling to come to terms with the loss of his beloved son, a soldier killed on patrol by an improvised explosive device.

America’s showdown with Saddam Hussein turned out to be a pretty big disappointment, except for those who got promoted, were awarded Presidential Medals of Freedom, or received fat advances to pen their memoirs. Certainly in Packer’s gallery of subjects, none found satisfaction with the outcome. Yet Packer for his part remains a true believer, stubbornly insisting that “the Iraq War was always winnable; it still is.” Indeed, were it not for the “criminal negligence” of those inhabiting the upper echelons of the Bush administration, he believes it would have been won long ago.

In essence, Packer suggests that because their motives were impure, Bush, Cheney, Rumsfeld, et al., really didn’t give the cause their best. Because their plans neglected the Iraqi people, a war that ought to have ended in triumph went awry. Members of Washington’s “ideological-industrial complex” scored debating points, advanced their partisan agendas, and feathered their nests, while conditions in Baghdad unraveled for want of sufficient troops and a clear plan for rehabilitating Iraq after Saddam’s removal. By 2005, a disgusted Packer declares, the war had become one more example of “a conspiracy of the old and powerful against the young and dutiful.” That’s a plausible conclusion, understandably appealing to an author committed to the proposition that the world’s only superpower ought to employ its military might on behalf of the oppressed and that it can do so without soiling its skirts.

There is an alternative conclusion, one suggested by Packer’s own reporting. That conclusion questions the extent to which war can serve as a remedy to evil. Although the political utility of violence is more limited than statesmen throughout history have believed, that political utility is real. Sometimes war is necessary. Yet even a necessary war such as the American Civil War or World War II leaves in its wake a train of pernicious consequences. In a moral sense, wars are never neat and tidy.

The American experience in Iraq has affirmed this truth. No doubt the arrogance, carelessness, and ineptitude of the Bush administration that Packer decries have contributed to our current predicament. But a deeper explanation lies in the nature of war itself. Precision weapons have not yielded precision warfare. Uncertainty and risk remain inherent in the use of force, as much in a high-tech age as when warriors fought with swords and pikes. Men pretend to have tamed war; the actual experience of war continues to show otherwise. As a consequence, to see force as an instrument of moral redemption is a delusion.

Anguished by the predicament of the suffering and oppressed, George Packer subscribes to that delusion. Vowing that his global war on terror will rid the world of evil, so too does George W. Bush. Iraq has not dealt kindly with the hopes of either. Sometimes the effect of diving into the sea is anything but cleansing.