The prominence of war in American life since 1914 constitutes "a virtual Seventy-Five Year War," wrote Robert Nisbet, the late political philosopher, in his 1988 book, The Present Age. It is way beyond obvious that war changes the societies of its participants, not always or entirely for the worse (the assumption that peace is the natural state of mankind can seem fragile upon reflection). Changes fostered by conflict, however, are likely to be dramatic, and Nisbet, rather despondent on the state of the union in what turned out to be his last book, observed, "All wars of any appreciable length have a secularizing effect upon engaged societies, a diminution of the authority of old religious and moral values and a parallel elevation of new utilitarian, hedonistic, or pragmatic values."

When, at last, the eleventh hour of the eleventh day of the eleventh month of 1918 came and with it an end to the horror of World War I, the British Empire counted a million dead, France 1.7 million. Two million Germans soldiers died, as did 1.7 million Russians, 1.5 million from the Habsburg Empire, 460,000 Italians, and hundreds of thousands of Turks.

The United States, which entered the war in April 1917, suffered far fewer casualties, of course. The first three Americans killed in combat died on the evening of Nov. 2, 1917, during a German raid on a trench held by members of the 2nd Battalion, 16th Infantry Regiment. The U.S. casualty list over the next year was 116,516 dead, 53,402 of them in battle, and 204,002 wounded in 19 months of U.S. belligerency; accidents and disease, especially the outbreak of the global influenza epidemic, killed more Americans than did bullets.

The "Great War," as it used to be called, is still a fitting description despite the vaster carnage of the rest of the century and the appalling transformations the war brought to the destinies of nations — from the grotesque tyranny of Lenin and Stalin to Hitler’s National Socialism. The changes in U.S. culture, politics, and economics as a result of the first war were not as ferociously and lethally consequential as those in Germany and Russia. But the changes World War I set in motion here were drastic even by the standards of a country that historically has embraced rapid change and been fascinated by it. The Cold War and the recent nastiness in the Balkans, too, have echoes from the 1914-18 war. Serbia was the fuse then, of course (long ago it was said that the Balkans produce more history than could be consumed locally), and the region’s current claim on our attention evokes fresh interest in World War I and makes it remarkably vivid.

"The First World War inaugurated the manufacture of mass death that the Second brought to a pitiless consummation," John Keegan writes in his new book, and "is inexplicable except in terms of the rancours and instabilities left by the earlier conflict." Keegan is one of today’s premier military historians, for years a senior lecturer at the Royal Military Academy at Sandhurst and the author of a baker’s dozen books, The Face of Battle and the recent Fields of Battle: The Wars for North America, among them. In The First World War, he concentrates on the Western and Eastern Fronts in Europe, where the most sanguinary fighting took place; he also recounts the more removed if no less significant episodes in Africa and the Middle East.

Keegan is both a rigorous historian and a narrative craftsman. He avoids the "presentism" that degrades a good deal of modem historical writing — the imposition of today’s standards and perspectives on the past. Thus, he carefully addresses the persistent notion of the British army as "lions led by donkeys" — that is, soldiers commanded by singularly, even criminally, incompetent generals. Some generals indeed were appallingly slow and worse. There was also, however, a technological gap between the massed firepower available and the primitive capacity to direct it in a precise and timely way. Communications were primitive, too — carrier pigeons were standard issue to units. Once the unfit and incapable were weeded out, the generals "came in the main to understand the war’s nature and to apply solutions as rational as was possible within the means at hand," Keegan writes. That is not a rousing endorsement, but it is fairer than glib condemnation.

Keegan is adroit at sketching character and the interplay of personalities in the politics of the war, among both the Central Powers and the Allies. He also writes with elegiac grace when the past is resurrected through the men who did the fighting and the dying (he writes of "Tommy Atkins," the long-service, "old sweat" troopers of the Empire who collectively comprised the British Expeditionary Force at the beginning and were nearly wiped out in the early battles at Mons and First Ypres, "Their patriotism was to the little homeland of the regiment.")

Byron Farwell’s Over There confines itself to the history of U.S. involvement after President Woodrow Wilson "kept us out of war" in 1916 and then reluctantly led the nation into it in April 1917. It is the tale of how America girded its loins after Germany resumed unrestricted submarine warfare and after disclosure of the Zimmerman telegram, explosive documentation of Germany’s intention, should the U.S. join the Allies, to lure Mexico into war against America and thereby reclaim its great tracts in the southwest.

Farwell (he died only weeks after his book was published) briskly covers the historical landscape of America’s lurch into mobilization and the young Americans who went off singing to save the world for democracy and learned the unforgiving drill of modern battle. His account is thorough and professional. (A history that mines deeper is The Last Days of Innocence: America at War, 1917-1918, by Meirion and Susie Harries, published in 1997).

By spring 1917, the horrendous lists of dead and wounded and missing had passed the point that either France or England could replace the numbers (never as critical a problem for Russia). Beyond the financial and materiel aid provided during the first two years of war, the most critical role the Allies envisioned for America was to supply manpower. A British-French delegation visited Washington two weeks after the U.S. declaration of war, and French Marshal Joseph Joffre insisted, "We want men, men, men." And it was the ability of the U.S. to put men in the field that would severely rattle the Germans, their own ranks irreparably thinning. By the summer of 1918, a growing malaise in the German army and a sense of "looming defeat" were attributed to "the sheer number of Americans arriving daily at the front," writes Keegan.

Although by 1913, the United States was the world’s largest economy, producing a third of global industrial product, it was just as well that the Allies were depending upon the U.S. primarily for healthy bodies. America had little else to offer at its entry into the war and not much more at the end. However, "What the United States accomplished in its nineteen months of war in raising an army and navy of nearly four million . . . was nearly incredible," Farwell writes, "but its armed forces retained all the marks of a hastily put together, partially trained, amateur affair, poor in almost everything except enthusiasm."

The month the U.S. declared war, the regular army mustered 5,791 officers and 121,797 enlisted men. It ranked sixteenth among the world’s armies, just behind Portugal, and remained as a secretary of the Army had described it six years earlier, "a profoundly peaceful army." The U.S. Navy at the outbreak of the war was less emaciated, though its combatant vessels were mostly undermanned and less than ship-shape.

Over There succinctly details the government’s immediate and vast insertion into American life. A conscription law was quickly passed and in a population of just over 100 million, 24 million men were registered and some 3 million draftees put on uniforms. The federal intrusion was beyond any previous American experience — though it was hardly executed with stunning efficiency. "In many instances the army took control of all stages of the manufacturing process, from finding raw material to inspecting finished products," Farwell writes. Herbert Hoover’s Food Administration regulated supply and consumption; Bernard Baruch became head of the War Industries Board with what amounted to "dictatorial powers."

The federal Committee on War Information, under George Creel, cranked up a propaganda campaign that was effective, pervasive, and exuberantly jingoistic. (James Montgomery Flagg’s Uncle Sam pointing sternly from a poster with the legend, "Uncle Sam Wants you" remains the most famous product of Creel’s media blitz.) There was an eruption of distrust, and occasionally worse, against "dangerous" alien influences in a nation that had seen a tidal flow of immigration in the past 30 years. "Between April and November 1917 thousands of suspected citizens were arrested, often without a warrant, and their backgrounds checked by the Alien Enemy Bureau of the War Emergency Division of the Justice Department," Farwell writes. "While most were released, about 1,200 were placed in internment camps." When Russia limped out of the war and Lenin took power, this fevered anxiety crested in the "Red Scare" under Attorney General A. Mitchell Palmer, compared to which the McCarthy furor was bush league in both method and substance. In 1918 Eugene Debs, union leader and founder of the Social Democratic Party, who spoke volubly against the war, was sentenced to 10 years in federal prison for violating the sedition provision of the Espionage Act. President Harding released him in 1921.

At the signing of the armistice at Compiegue, no Americans were present. President Wilson had unveiled his "Fourteen Points" the previous January without any consultation with the Allies, Congress, or any member of his own Cabinet. But publics here and abroad wildly cheered his idealistic flourish — and the Wilsonian agenda was blithely ignored as the peace conference carved up Europe and eagerly punished Germany. (Of the Fourteen Points, French Premier Georges Clemençeau derisively observed that God required only 10.) The centerpiece, a League of Nations, was stillborn. Twenty-one years later the bill from Versailles came due, and in a sense is still being paid in Yugoslavia.

As after World War I, so after World War II, the U.S. demobilized with the same furious energy in which we went to war — and we were caught in our bunks, as it were, when Korea exploded five years later. Several thousand gis paid the full tariff for that unreadiness in the first few weeks there. America’s tendency to have to go to war from a standing start has a disconcerting historical consistency, and it is to be devoutly hoped that that past is not always prologue.

If, as Nisbet contends, the U.S. since 1914 has participated in a continuous war, that much was not apparent in the interwar years. Indeed, the corporal’s guard to which the American military was reduced after the first war suggests that the U.S. was more demilitarized than active. By the end of 1919, America’s regular army was reduced to about 19,000 officers and 205,000 enlisted; by 1925, it totaled 135,000. Had it not been for a core of professional soldiers who made sensible deductions from their experience in the first war and devoted their careers to keeping the U.S. from relapsing into a pre-1914 anachronism — Billy Mitchell on air power, George Patton and Dwight Eisenhower on armor, for example — in World War II it likely would have required far longer to deploy the indomitable forces America put in the field, and at a far higher cost in blood and bucks.

A nation’s armed forces are a reflection of the civil world. It is provocative to consider Nisbet’s assertion of "a diminution of the authority of old religious and moral values and a parallel elevation of new utilitarian, hedonistic, or pragmatic values" in a society in an extended state of war. His is a distinctly despondent prognosis, and it is doubtless true. Up to a point.

There may also be correlation as much as causation in such a formula, however, in a country that habitually leaps on its horse and rides off imaginatively in all directions. Utilitarian and moral values in the U.S. historically have coexisted, if usually in straining harness, sometimes one ascendant, sometimes the other. In a land as prodigiously various as the United States, the balance is always fitful. The fractious debate over morality and spirituality in the waning twentieth century would argue that so static an equation as Nisbet’s commends itself mostly to the implacably pessimistic.

There is, though, an aspect of World War I that offers itself both as a metaphor for the years since and an index of our national evolution since the first war. John Keegan brings it front and center. European military planning traditionally had been made "on the hoof," as he neatly puts it — plans fashioned only when war threatened or actually began. By the nineteenth century, though, the ad hoc quality of planning began to be "systemized." The Prussians were the innovators in establishing staff colleges, with the French and British following not far behind. War planning was elevated to a function beyond and even divergent from national diplomacy. Numerous operational scripts were minutely prepared to cover both defensive and offensive contingencies; in the decades before the first war, for example, general staffs made a point of compiling the most intricate railroad timetables for mobilization and troop movements.

The systemization of military planning could not exist in a social void, involving as it did every aspect of a nation’s resources. Thus, war planning of such broad scope assumed political as well as economic and military consequences — indeed preeminent consequences once war began.

The most lasting effect of World War I in the United States has been the "systemization" of society — centralization of government power and regulation. To be sure, the experience of the war alone did not account for what has been a continuous expansion of federal authority. The Great Depression and the second war rationalized the accretion of power in Washington, philosophically pushed along by "progressives" who levitated to influential levels in the opinion-shaping leagues of academia and the press.

A central government once well emplaced and practiced, whether in the exercise of increased social or military power, does not automatically recede to a status quo ante — indeed, it resists curtailment. It is not in the nature of power or institutions to shuffle off once the moment of evident necessity has passed. The military may shrink rapidly when peace comes, but its civilian masters do not (which is further proof, if more were necessary, that the military remains subservient in American society).

For better or worse, however, it is the nature of a citizenry, or at least a functional portion of it, to acquiesce to such transformations as if somehow ordained. Each generation tends to regard the structure of power it encounters to be generally legitimate, having experienced only that status; the dissenters, for whom a freer, less trammeled vision of government beckons, will struggle to roll back the longest tentacles of the regulatory beast.

Never before 1917 had the federal government assumed such penetrating authority over the private sector. Abraham Lincoln’s intrusion into civil liberties and his stimulus of American industrial muscle (muscle already poised to flex with awesome energy) were modest in comparison with those during World War I — just as Franklin Roosevelt’s immense Depression-era and World War II mobilization of government management dwarfed that of World War I. World War I was a template and precedent for the future, if obviously not the only factor. Verging on a fresh millennium, America today, with three times the population of 1917, federally systemized from stem to stern, resembles the country that entered the last century as a faded photograph in an old family album.

This is not an unrelievedly grim perspective. The strength and spirit of the United States have created a contemporary citizenry with enviably greater opportunity and choice than was conceivable a hundred years ago. Notwithstanding the apparent acclimation to a central authority that often overwhelms its constituent parts, there remains sufficiently robust suspicion of centralized authority to keep the bureaucracy and its political masters looking over their shoulders. And despite the continuing influence of a sometimes brittle Wilsonian moralism in foreign policy, a complementary debate over specific national interest and criteria for intervention abroad helps sustain a precarious balance.

Contrary to the blather during the Vietnam years about the arrogance of power, there is a compelling responsibility of power. The United States has accepted that burden and fulfilled it with tenacity and courage, from 1917 to now. There is a price for exercising that power, of course, and it is always more than one would wish to accept. It is to this nation’s honor that, though we have flinched and often muttered, America has not defaulted — with the dismal exception of abandoning South Vietnam without the support we had pledged.

There is another legacy of World War I for which an argument can be made. Despite the rise of totalitarianism across much of Europe after 1918 and the sacrifices required to defeat Nazism and then to resist communism until the Soviet Union crumpled, liberal democracies now are the prevailing governments over most of the Continent. If it required 81 years to make a decent portion of the world safe for democracy, at a fearful cost, nonetheless safe it now appears.

Byron Farwell quotes Liddell Hart at the close of Over There. "The United States did not win the war, but without their economic aid to ease the strain, without the arrival of their troops to turn the numerical balance, and, above all, without the moral tonic which their coming gave, victory would have been impossible."