Soldiers of the State.

The Shield of Achilles: War, Peace, and the Course of History, by Philip Bobbitt (Knopf, 919 pp., $40)

Robert Stewart, second viscount Castlereagh, was the British foreign minister from 1812 to 1822. A member of the Irish peerage, melancholy, aloof, in many ways mysterious, he won a place in the British cabinet; there he labored, during the last decade of his life, to turn the coalition of Great Powers leagued against France into a peacetime alliance capable of establishing, and preserving, order in Europe.

To a large extent he succeeded. In 1814 the allied powers -- Great Britain, Russia, Austria, and Prussia -- pledged to maintain a collective-security arrangement that would survive the defeat of Bonaparte's France. This "Concert of Europe" was ratified a short time later by the Congress of Vienna; Castlereagh dared to hope that its very existence would tend to promote the stability of Europe. In the future an aspiring conquistador, eager to emulate Bonaparte or Louis XIV, would no longer be able to rely, as those princes had, on a strategy of divide and conquer; he must consider instead that any attempt to enlarge his country's territory would draw upon him the wrath of a united coalition.

Reviled as a malignant schemer, a diplomatist deep in the cabals of Metternich and Talleyrand, Castlereagh was as misunderstood, in his own day, as the farsighted man tends to be -- or so Philip Bobbitt argues in his excellent new book, The Shield of Achilles. On August 12, 1822, Castlereagh committed suicide, but his contributions to the theory and practice of collective security outlived him, and retain their value even today. Bobbitt believes that alliances formed on the viscount's logic -- NATO, for example -- will continue to be effective in the new era we are entering, while other approaches to order -- such as the United Nations and the European Union -- will prove even more useless in the future than they have in the past.

The thoughtfulness of Bobbitt's portrait of Castlereagh will give the reader some idea of the interest and intelligence of this book. The author's ability to bring a diplomatic drama to life is doubtless related to his own experience; he is a rare combination of philosopher and public servant. He has taught not only at the University of Texas, but also at Oxford and the University of London; he has served as a counselor to presidents on matters of national security, and to senators in connection with the Iran-Contra affair. He has been sensitive to each of these environments, and this sensitivity is reflected in the worldliness of his analyses. His urbanity is not merely intellectual; he has a highly developed and quite unacademic feeling for power, a feeling attainable, perhaps, only by those who have had some share in its exercise.

The state exists, Bobbitt notes with characteristic lack of sentimentality, because it is able to hurt people. Violence is its metier. It is this, the state's ability to act violently, that enables it to protect its inhabitants both from external threats (foreign enemies) and internal violence (criminals). But the forms that violence assumes are not static; new, more concentrated, and more lethal forms of violence are continually being developed. If a particular state is to survive, it must adapt to the changed realities, and find ways both to defend against and to deploy the new machineries of violence.

In the 15th century the Ottoman Turks assembled artillery powerful enough to pound the walls of Constantinople into rubble. In 1453 the city fell, and European princes trembled. No wall exists, Machiavelli wrote, "however thick, that artillery cannot destroy." This innovation in weaponry, Bobbitt shows, produced a corresponding revolution in the state. In order to defend against the new threat, the Italian princes implemented a series of far-reaching policy changes. The resulting renovation marked the emergence of a new form of constitutional order, the "princely state."

The Shield of Achilles traces the successive revolutions in strategy and constitutional thought that created, over time, the modern state. Innovations in tactics sometimes drove constitutional change. The infantry countermarch of the 17th century, for example, solved problems caused by delay in the reloading of muskets; but this elaborate drill could only be performed by closely disciplined troops. Armies capable of maintaining such esprit de corps could not be accommodated within the structures of a princely state, and intelligent statesmen set out to remodel their outmoded constitutions. In France, Cardinal Richelieu worked to transform the "princely" Valois constitution into a "kingly" Bourbon one -- the instrument that enabled Louis XIV to field, for a time, the most powerful armies in Europe.

In some cases, constitutional developments dictated changes in tactics. Bonaparte, for example, was at the head of an army in the revolutionary turmoil that made France what Bobbitt calls a "state-nation." Even the Corsican, with all his military genius, could not hope, in such conditions, to impose upon his troops the rigorous discipline of Frederick the Great. He instead found ways to channel into the army the immense patriotic enthusiasm inspired by the French Revolution. He exploited the strategic possibilities inherent in the levee en masse, or universal male conscription; and for a time his gigantic citizen- armies were irresistible in Europe.

Bobbitt grasps brilliantly the interplay of strategic innovation and constitutional change that made the modern state; but he is less sensitive, I think, to the third force at work, that of spiritual aspiration. A number of the constitutional mutations he analyzes came about, in part, because men sought a substitute for the unity of endeavor that had vanished with the passing of the Middle Ages. A desire to recreate the broken wholeness is evident in the efforts of citizens to revive, in the Italian peninsula, the civic life of Athens and Rome. It was in France, however, that the most thorough attempt was made to recreate, in the new environment of the state, a semblance of the old medieval coherence. Here was a kingdom in which, by the end of the 17th century, the political, spiritual, and economic life of the people revolved around the king. Louis XIV was the "roi-soleil" at the center of the new universe. Bossuet, the court preacher, believed that the monarchy, a "sacred" institution, was central to the spiritual meaning of France; Colbert, the finance minister, showed that Versailles could play a no less vital role in superintending the economic development of the realm.

The absolutist model of Louis XIV was never intended to be merely an archaic revival; on the contrary, Bossuet believed that kingly government was an ongoing work of "reason and intelligence." If the poetry of state was centralized in the drama of kingship, the intellect of the kingdom was concentrated in the royal ministries. This massing of bureaucratic brainpower was meant to facilitate progress through the rational direction of affairs; and the royal mandarins, charged with refining the principles of the Bourbon solar system, strove to reduce France to the geometrical order of a garden at Versailles.

It was at this time that an alternative model of governance was fashioned in England. There the "kingly state" never ripened into maturity. The Tudors, it is true, laid the foundation for such a state, and the Stuarts attempted to build upon it. But they failed: The idea that the political, spiritual, and economic life of the kingdom could be wrapped up in a coherent bundle was rejected as impracticable, and the various departments of life were allowed to operate independently of one another. Nor would there be, within any particular department, an insistence upon organic unity; people would instead take their politics, and even their religion, much as they took their other household goods -- by going to the market and seeing what was on sale, and at what price.

A great deal that is valuable in the modern "market-state," as Bobbitt calls it, was implicit in the legislation enacted by the Whigs after the Revolution of 1688. The Bill of Rights (1689) secured the "rights and liberties of the subject"; the Toleration Act (1689) protected certain categories of religious dissent; the Triennial Act (1694) required the "frequent meeting and calling of Parliaments"; the decision not to renew the Licensing Act emancipated the press. To the early years of the Whig regime may be traced, too, a number of innovations in the infrastructure of the capital markets, among them the creation in 1694 of the Bank of England -- which gave England interest rates lower than those on the Continent.

William III confirmed the Whig settlement partly for military reasons: Regulation was costly, and he needed cash to fight the Sun King. A long, desperate struggle between the two contending systems ensued; but although England eventually triumphed over France, the victory did not doom the principle for which the French fought. It is true that France began to move, after the defeat of Bonaparte, in a Whig direction; and in the days of Guizot and the July Monarchy French liberalism reached its zenith. Russia and Austria, however, two of the signatories to Castlereagh's 1814 pact, remained committed to the autocratic model of Louis XIV, and sought to defend it through a Holy Alliance with Prussia.

Philosophers, meanwhile, devised new theories by which the felicities of a communal existence could be secured without resort to an anachronistic absolutism. Romanticism supplied a theoretical justification for nationalism; bogus economic science and esoteric German philosophy, rearranged by Marx, supplied the basis for another theory, which held that men and women could realize their innate sociability through new forms of communal organization. These communes, it was believed, would be a great advance over the fragmented and hypercompetitive existence fostered by liberalism.

In the dark genius of Bismarck these two strains of communal longing were brought together. Bismarck's ambition was to sort the European peoples into their aboriginal "tribes"; and amid scenes of tribal ecstasy he united the German nation. The old Junker then proceeded to lay the foundation for the quasi-socialist Wohlfahrtstaat. Hitler, who perceived the crueler possibilities in these policies, carried them to an extreme: he called his program "National Socialism." These developments were paralleled in Russia: After the collapse of tsarist absolutism in 1917, the Bolsheviks attempted to implement a form of Marxian socialism; but Stalin, the consolidator of the Russian Revolution, recognized that socialism by itself could not secure the state. He began knitting nationalist threads into the fabric of the socialist constitution, and in order to fight the "Great Patriotic War" he revived the mystique of Mother Russia.

Bobbitt's book, splendid though it is, would be even more persuasive if it brought the reader to see, in the various wars with which it deals, the larger struggle between the aggrandizing communal regimes and the market-oriented free states. What Bobbitt calls the "Long War," in the 20th century, among the liberal democracies, the Axis powers, and the Soviet Union, seems to me to have been one episode in a continuing fight between those who accept the liberal (Whig) dissociation of experience and sensibility, and those who yearn for the simplicity and coherence found in a state where every aspect of existence is subjugated to a transcendent ideal. Such a narrative would help the reader to see that, although the liberal democracies prevailed in the Long War, their victory came at the price of some of their anti- totalitarian principles. Americans tolerated, in the middle of the last century, a highly militarized state, punitive tax rates, and a centralizing regime in Washington.

Now that the latest fight has been won, Bobbitt writes, statesmen should concentrate on refining market-based order. And yet the keepers of the market-state cannot relax their vigilance; the United States, Bobbitt argues, must pursue missile defense and take the lead in establishing security coalitions on the NATO model.

This book -- with its masterly reappraisal of modern history and subtle elucidation of today's geopolitics -- should be on every desk in the State Department. And yet it cannot answer -- perhaps no book can -- the largest question now before us. We have still to find a way to appease those yearnings for coherence, that quixotic passion for a unifying ideal, which may again grow strong enough to upset, once more, the precarious order of the free states.