In the imperial weeds: in his travels with special forces on the frontier of America's empire, Robert Kaplan captures the gritty realities, but not the paradoxes.

Imperial Grunts: The American Military On the Ground By Robert D. Kaplan Random House, $27.95

There are a few things you might need to know about Yemen. If you're kidnapped, don't get too upset; you're probably just a bargaining chip in some tribal bid for a new water well or a road. Kalashnikovs are everywhere, and so are the long curving daggers known as jambiyas, every local man's obligatory fashion accessory. If you want to bring along presents for local notables, big knives will do fine. Cell phones are popular, as is the Arabic-language satellite TV channel Al-Jazeera, even if, as Robert Kaplan advises us, Yemenis tend to view it as "provocatively Westernized." When socializing, you may find yourself having to chew large amounts of the mildly narcotic weed known as ghat, which has, Kaplan notes, "an exquisitely subtle effect at once energizing and relaxing, like having five cups of espresso without feeling overwound."

Oh, yes, and don't forget that Yemen just happens to be a key strategic location in the post-9/11 GWOT (Global War on Terrorism). Osama bin Laden's family originally comes from the Hadhramaut, the desolate hinterland bordering Saudi Arabia. Not long before Kaplan's arrival in 2003, the CIA rubbed out an alleged Qaeda operative by blasting his car with a missile fired from a Predator drone. And it's not over yet. As Kaplan describes it, the country is a classic breeding ground of early 21st-century terrorism, a place where modernization and tribalism collide to devastating erect. As such, it poses exactly the same sort of challenge that faces the United States and its allies on myriad other fronts across the world.

This remarkable, intriguing, and frequently frustrating book is essentially a GWOT travelogue, a dizzying grand tour of some of the places--largely neglected by the mainsntream media--that figure in this struggle. But just in case we get blinded by the exoticism of his locales, Kaplan is ready with a useful antidote. Look back to history, he says, and we'll realize that the whole thing is just a matter of deja vu all over again. For the U.S. military, one particularly useful template is America's own Indian Wars of the 19th century. (Yemen, says one American there, is "Injun Country.") But Hadrian or the young Winston Churchill, Kaplan argues, would have found plenty that was familiar to them as well. For what we're observing today is the classic imperial paradox at work. The story of the 20th century was the struggle for supremacy among several great powers, expressed in a series of huge, set-piece conflicts. Today, by contrast, American hegemony is challenged by an amorphous international grouping of fanatical insurgents, more a "brand" than an organization, that doesn't even rely on the perks of state sponsorship. That makes them almost impossible to spot, and because they feed on the profound tensions inherent in the very process of globalization, they are exceptionally hard to uproot. As Kaplan perceptively notes, "[T]errorism is both a cause and a symptom of the political weakness of states like Yemen. So, in a sense, the U.S. was fighting the unwieldy process of modernization itself."

And what all of this has inevitably spurred--whatever our original intentions--is a largely improvised, haphazard process of American imperial expansion, as U.S. power rushes in to fill the ensuing vacuums. The primary agents of this process are not the policy-making elites in Washington, Kaplan writes, but American soldiers on the ground, often relatively low-ranking non-commissioned officers (the "grunts" of the title) making day-to-day, deeply pragmatic decisions in response to a bewildering array of local problems. From time immemorial, Kaplan insists, this is how empires have grown, and his mission is to provide a "snapshot" of this process at a pivotal moment. For Kaplan, empire-building is not about using big armies to conquer people; it is a mess of squishy, microcosmic doings along the fuzzy border between war and diplomacy, prosecuted most effectively when it's all happening outside of the media spotlight (his own excepted, of course). In situations like these, less is usually better--a principle known at the Pentagon as "Economy of Force." In Colombia, Kaplan watches approvingly as a tiny group of U.S. Special Forces advisers bolsters the shaky Colombian army against a powerful narco-insurgency, and recalls 1980s E1 Salvador, where, he writes, "fifty-five Special Forces trainers accomplished arguably more than 550,000 troops in Vietnam." In the southern Philippines, another small group of S.F. operatives help the army of the Manila government to isolate Muslim insurgents allied with al Qaeda. That can mean training Filipino soldiers how to fight in the jungle at night, but it can also mean digging wells or fixing local peoples' teeth. In Mongolia, he trails along as the American military attache conducts a marvelous one-man diplomatic campaign. By spreading goodwill along the host country's sensitive frontiers and wooing key players in the military hierarchy, Lt. Col. Thomas Wilhelm is banking that Mongolia will make the right choice on that distant day when the Pentagon suddenly finds itself needing a plausibly deniable listening post or a low-profile logistics base in the region.

Kaplan, who describes himself as an unabashed believer in the essential goodness of American nationalism, makes no bones about his urge to argue the case about this grand undertaking, and he is happy to step on as many liberal toes along the way as he can. He interviews a Philippine villager whose "smiling, naive eyes cried out for what we in the West call colonialism." It's the sort of thing clearly calculated to raise hackles--but this kind of gratuitous provocation tends to get in the way more than it helps. Which is a pity, bemuse there are plenty of places in this book where liberals need to take their medicine. He's certainly correct to point out, for example, that much of what we blissfully refer to as "globalization" is predicated on the existence of a world policeman who keeps the sea lanes open and prevents minor geopolitical conflagrations from flaring into large-scale wars (very bad for business). I also liked his argument that a liberal political culture at home has never been implicitly at odds with a program of imperial expansion in the world at large. "Some denied the very fact of American political empire, claiming a contradiction between an imperial strategy and America's democratic values. They forgot that Rome, Venice, and Britain were the most morally enlightened states of their age." He also provides a vivid and urgently needed case study of how the top-heavy force structure in Afghanistan prevents U.S. commanders from flexibly deploying forces in the field against an elusive and highly mobile enemy. The reality on the ground, in other words, doesn't really square with the upbeat Rumsfeldian talk of a new, nimble fighting force. Observing the U.S. Marine offensive in Fallujah, Kaplan returns to an point that should, for different reasons, nonplus many on the right as well as the left: "The American Empire of the early twenty-first century depended upon a tissue of intangibles that was threatened, rather than invigorated, by the naked exercise of power."

What a cool insight, the reader thinks--tell me more. Unfortunately, that's pretty much where the author stops. For all this book's admirable strengths, Kaplan's chronic weakness--mistaking allusion for analysis--has never been on more vivid display. Never mind, for example, that he never gets around to defining precisely what he means by the highly loaded word "empire"--by its actions ye shall know it, I guess. Most of us seem to associate the idea with conquest, a metropolitan power subduing smaller countries on its periphery and subordinating them to a larger political unit. But that's clearly not what we're dealing with in the present case, as the author concedes. In one aside he notes: "Indeed, America's imperium was without colonies, suited to a jet-and-information age in which mass movements of people and capital diluted the meaning of sovereignty." Whoa! So, in other words, we live in an age that has diluted the very meaning of empire as well? This is mighty stimulating but leaves more questions open than it answers:

I would argue strongly that this is not just a matter of dry academic interest. As near as I can tell, ask most Americans if they want to be part of an empire and they will say, decisively, no. How well I remember an excellent commentary by my Newsweek colleague Christopher Dickey, who described sitting in the bar of the Raleigh-Durham Airport shortly after President Bush's "Mission Accomplished" speech and noting that all the TVs had been turned back to golf and NASCAR. As Dickey wryly observed, "They were tired of the war, even tired of winning it." How right he was--and that was the late spring of 2003. What about now? Kaplan would presumably respond that the Roman mob was happy with its bread and circuses, too, leaving the legionaries to do the heavy lifting.

I don't think it's that simple, though. Nowadays, unlike Roman times, it's taxpayers that foot the bill of expansion. So, what about the paradox of an empire that no one wants to pay for? As Kaplan notes in passing, despite all the patriotic effusions and heady talk of global destinies, defense spending as a percentage of GDP is at its lowest level in historical memory (3.3 percent--compared to 9.4 percent during the Vietnam War or about 40 percent during WWII). Economics doesn't interest him particularly, either, though you'd think it would play much more of a role in a book on geopolitics. Here, for example, all we get is a few dark mutterings about containing burgeoning Chinese influence, and Kaplan has recently written, in The Atlantic Monthly, about the threat of a coming "Cold War" with China. Well, I guess that's certainly possible. But I will be interested to hear how we plan to conduct a war, Cold or otherwise, against a country that owns a sizable chunk of our Treasury debt.

And what about the conundrum of an empire without soldiers, as recruitment levels collapse? Our magnificent all-volunteer, all-professional army may be doing a little bit better in recent weeks, but the very idea is looking shakier than it has since we started it after Vietnam. I observed firsthand the disastrous effects of the Pentagon's stop -loss policy during my own time in Iraq, as reservists and National Guardsmen watched in rage as their terms of deployment extended far beyond what they had been told to expect. It would seem that our empire-builders are hell-bent on destroying our army.

And it's not that Kaplan ignores the home front. He is quite obsessed with the issue of class and how it affects relations between the military and the worlds of academia, government, and the media. But even though this is a topic of crucial importance, it's hard to figure out what he's trying to say. On the one hand, he heaps scorn on the coastal policy elites who spend their days in the clouds, whipping up goofy theories that never have to be tested against reality, while the Real Men of the military, who am enviably unselfconscious about their evangelical Christianity and their fondness for hunting and stock-car racing, make the decisions that really matter. But those policy elites with no history of service include the same neoconservatives who plunged the country into war--and whose orientation he shams. Working-class stiffs am more willing to die for the country, he says at one point, because of their "rough, unfair lives and turns." Elsewhere, though, Kaplan explains the remarkable competence of American NCOs with the "relative absence of class envy" in the American armed forces, the "revolutionary dynamism" of the "great middle." So, which is it? Are Kaplan's heroes mindless working-class stiffs, or empowered middle-class meritocrats? Kaplan seems to be suggesting that there's a potential problem here with some kind of class distinction between those who run the country in Washington and those who do its dirty work out on the frontier, but he never gets around to addressing what we might do about it. Arguments for or against the military draft, the one tool government might use to change this state of things, are striking by their absence.

This book is still a hell of a ride, and by the end, I was green with envy at Kaplan's breadth of travel and tremendous access. (It turns out that they love him in the Pentagon. Who would have thought?) But I was glad, in the end, that I had taken the trouble to don my intellectual body armor before I dove in. Sometimes Kaplan's cheerleading is just a bit much. He presents himself, with disarming honesty, as a thoroughly biased advocate for the imperial project--a claim directly contradicted by his assertion, at another point, that he merely wants to provide an objective picture of what he sees in his travels. As an aspirant to the mantle of the Kipling of the 21st century, Kaplan more than delivers. The book is oversupplied with heartwarming cameos of our boys in the field. "Pat Gleason, like many noncommissioned sergeants and warrant officers I would meet in the course of my travels, was quietly amazing" Another grunt "looked like the all-American kid on a milk carton." "Every aspect of his lined face and short, wiry body seemed hard and chiseled.... I imagined Ligustinus, the Roman centurion who had served in Spain, Macedonia, and Greece." "Capt. Murray had a velvety voice and smile that mothers everywhere fall in love with, even as his uniform hid a muscle mass straight out of a bodybuilding magazine." "I was beginning to love these guys." Yeeeeee. Maybe Kaplan's S.F. supermen are made of sterner stuff, but the Florida National Guardsmen I covered in Iraq would have cringed at this sort of thing. They were just happy to see me doing my best to get the story right. They certainly didn't want to be serenaded. And so it should be. As any true grunt knows, building empires is not a pretty business.

Christian Caryl is the Tokyo Bureau Chief of Newsweek. He has reported from 35 countries, including Afghanistan, Iraq, Russia, and North Korea.