If this book can be said to have heroes and villains, the heroes are the Marines and the villains the one-dimensional army thinkers like William Westmoreland and Colin Powell whose strategies have been a disaster for American arms and prestige. Max Boot, the editorial features editor of The Wall Street Journal, has examined the limited wars that dominate American military history and are the rule to which the Civil War, the two World Wars, and Korea are the exceptions. These limited wars can be variously termed, among other things, counterinsurgencies, sublimited wars, low-intensity conflicts, or the wonderful new coinage “military operations other than war,” but Mr. Boot settles on “small wars” (the actual translation of the Spanish “guerilla”).

In the post-Civil War era, the Marine Corps, which had existed in various forms since 1775, gained a motto, a march, and a mission. The government was beginning to take an interest in the Caribbean and the Pacific, and troops were needed to help stabilize some very unstable countries. The missions tended to take four basic forms: punitive raids or campaigns, protection of Americans or American interests in a foreign country, the pacification of rebellious and marauding populations, and the annexation of land or trade concessions (Mr. Boot calls this last item “profiteering” to maintain the alliteration). Between 1898 and 1940, Marines fought “small wars” in China, the Philippines, Cuba, the Dominican Republic, Haiti, Nicaragua, Panama, in some cases more than once and often on a long-term basis—four decades in China, for instance. These assignments earned the Marines the nickname of “State Department troops.” But they were very good at them and proud enough of their achievements to cite the motto “Can Do” to go along with “Semper Fidelis.” The Marine Corps’s own Small Wars Manual (1940) notes that “Small wars represent the normal and frequent operations of the Marine Corps.” (This is not to forget or undervalue the U.S. army’s campaign in Mexico against Pancho Villa in 1916–17 and the troops committed to the Russian Civil War from 1918–1920, both of which are featured in the book.)

One of Mr. Boot’s key points is to refute the idea that U.S. intervention was to protect business interests at the expense of legitimate states. He shows that the United States generally landed in the countries with the least U.S. investment and the most instability—ones generally threatened by insurgencies and coups—hardly good places to do business. The United States tended also to employ a supremely effective variation of the carrot and the stick: the U.S. troops not only fought a bold and sometimes vicious campaign against the insurgents, but also built roads, hospitals, sewer systems, schools, and a general healthier and more prosperous life for those who gave up fighting. Mr. Boot shows that in these countries the United States was generally what stood between chaos or despotism and the reasonable rule of law. The United States was heavily criticized for its intervention in Haiti in 1915. Yet in reality U.S. troops were what kept out the dictators. In nineteen years of occupation, the Marines built 1,000 miles of roads, 210 bridges, 9 airfields, 11 hospitals, 147 clinics, etc. As Mr. Boot points out, “Having arrived in Haiti to the sound of gunfire, they left to the tune of the Marine Corps anthem, belted out by the Garde d’Haiti band.”

The 1940 Small Wars Manual seems to stand as a marking point in U.S. military policy. It came out just as we were to embark on our largest and most successful war. The victory in World War II heralded a new way of waging war and led many to refer to total war as the “American Way of War.” But as we went forward, the tactics and strategy that won against Germany and Japan failed us. As the manual points out, small wars are ambiguous assignments, “to establish and maintain law and order by supporting or replacing the civil government in countries or areas in which the interests of the United States have been placed in jeopardy.” This is, moreover, to be done “with the minimum of troops, in fact, with nothing more than a demonstration of force if that is all that is necessary and reasonably sufficient.” The Marine Corps was remarkably successful at small-war fighting with a minimum of troops—except during the World Wars, the Marines never numbered more than 20,000 total and often less than 10,000. But the lessons of the successful “small wars” were forgotten in the Cold War.

Our bumbling and bungling war in Indochina is a familiar story. Mr. Boot focuses on the failures of military strategy. And General Westmoreland must shoulder this burden, not only for trying to fight a counterinsurgency with total-war tactics, but also for failing to have the imagination to see his failures and adjust. It used to be that the American genius was for getting things right in the end. We might be unprepared but our native skills for improvisation and innovation would see us through. Our general command staff in Vietnam fought like a stack of Prussians who never thought, but only did. Mr. Boot’s analysis of Vietnam post-Westmoreland is excellent, and he rightly points out that the U.S. troops under Creighton Abrams won the military conflict and pacified the population; they even trained a South Vietnamese army capable of repulsing the Viet Cong with U.S. air and logistical support. But we lost the war at home and so we left our allies to their fate.

It is at this point that our second villain appears: Colin Powell. Mr. Boot quotes Secretary Powell as saying “Many of my generation, the career captains, majors, lieutenant colonels seasoned in [Vietnam], vowed that when our turn came to call the shots, we would not quietly acquiesce in halfhearted warfare for half-baked reasons that the American people could not understand or support.” Working under Caspar Weinberger in the 1980s, General Powell developed a military doctrine that I would term “Don’t Ever Fight.” These two secretaries of defense set forth a long sequence of preconditions for employing our troops: no deployment unless it is vital for our national interests, unless we are committed wholeheartedly to winning, unless the military objective is clear, unless there are actual means to the end, unless there is popular and congressional support, and—added later—unless there is an exit strategy. The doctrine also includes the fabulously stupid statement that “finally, the commitment of U.S. forces to combat should be a last resort.” Can you think of any war in history that fits all these criteria?

The Powell Doctrine survived three administrations and a number of spectacularly unsuccessful engagements—think Haiti and Somalia. It took two jetliners slamming into the World Trade Center for its core assumptions to be challenged. (It is interesting that the most passive military doctrine since appeasement was undone not by Blitzkrieg-like fighting, but by men wielding box cutters.)

Mr. Boot’s analysis is very compelling and sensible. The only possible criticism of the book is that the narrative of the many small campaigns the United States waged in the years before Vietnam is presented without enough context and with an over-reliance on the biographies of a few colorful individuals from Stephen Decatur and David Porter to Fighting Fred Funston and Smedley Butler. It is the nature of a general history to do so, but I still wish Mr. Boot had fleshed out the stories and given readers a larger sense of such issues as the American refusal to build an empire in the eighteenth century even after losing trade opportunites to such acts as the Dutch colonization of Sumatra. But it seems churlish to make any complaints. The Savage Wars of Peace is an important book, which teaches a real and essential lesson about American foreign policy makers and army generals. May we heed its lessons in the years to come.