"The past," the novelist L. P. Hartley wrote, "is a foreign country; they do things differently there." There is certainly much that is alien about the world of Robert Stewart, better known as Lord Castlereagh (1769-1822), who helped usher in a new European order as British foreign secretary during and after the Napoleonic Wars. Nowadays, for example, one would not expect two senior politicians from the same party, both cabinet ministers, to fight a duel in the middle of a war, as Castlereagh and then Foreign Secretary George Canning did in 1809. And of course, there were some more fundamental differences: the British government of Castlereagh's day was elected by a narrow, all-male franchise determined by property ownership, and King George III, in his saner moments, was no mere constitutional figurehead but a power in his own right. Outside Great Britain, continental Europe would seem stranger still, with systems ranging from the Napoleonic tyranny in France to absolute monarchies in Austria, Prussia, and Russia. In international politics, wars of aggression and territorial annexation were still the norm.

But there is also much that is familiar about this world. Castlereagh's career played out in a parliamentary setting of intrigue and political maneuvering not dissimilar to those found in Washington and London today. In the international arena, Castlereagh confronted a landscape fractured by diverging national interests and profound ideological cleavages that would be recognizable to any modern diplomat. Given these resemblances, Castlereagh's successful management of competing great-power aspirations continues to resonate, inspiring statesmen such as former U.S. Secretary of State Henry Kissinger, who wrote his doctoral dissertation at Harvard on the subject; the former British foreign secretary Douglas Hurd, who wrote a book that favorably contrasted Castlereagh's careful diplomacy with the more unilateralist tendencies of his contemporaries and successors; and the United Kingdom's current foreign secretary, William Hague, who wrote a 2005 biography of Castlereagh's boss, Prime Minister William Pitt, the Younger. What draws modern statesmen to Castlereagh, Hurd wrote, is a shared belief "in quiet negotiation, in compromise, [and] in cooperation with other countries . . . which could span an ideological divide." The followers of Castlereagh distinguish themselves from proponents of "a noisier foreign policy," based on unilateral action, liberal sympathies, and a penchant for intervention.

In a new biography, the historian John Bew revises this classic view, presenting Castlereagh as more ideological and less realist (but no less realistic) than the conventional portrait. The result is a magisterial guide to Castlereagh's life that should inform the general understanding of international politics today. Even among highly educated people, few remember more about Castlereagh than his name. But one can draw direct links between his ideas and many features of contemporary world affairs, including institutions such as the United Nations, disputes over sovereignty, humanitarian interventions, and wars of preemption and prevention. Castlereagh's career also offers many enduring lessons for Europe in its current time of crisis: that the United Kingdom must play an active role on the continent, that Germany is the focal point of the European system, and that Europe should strive toward ever-greater unity in order to master its internal and external demons.


At the heart of Bew's narrative is a masterly account of Castlereagh's diplomacy, which was based on an unshakable belief that maintaining a balance of power in Europe was central to the United Kingdom's security. Like most members of the British political class, Castlereagh was deeply concerned about the growth of France's power: 20 years after the outbreak of the French Revolutionary Wars in 1792, Napoleon Bonaparte controlled the vast majority of continental Europe outside Russia. In 1812, Castlereagh became both foreign minister and leader of the House of Commons, which gave him almost as much authority in domestic affairs as he had in foreign policy. But the apogee of Castlereagh's career came in 1814, when he forged the coalition of states that finally defeated Napoleon and won the right to shape a new European order. "He has long governed England," Castlereagh's brother wrote at the time, "and is [now] . . . governing the continent."

In addition to his suspicions of France, Castlereagh was wary of the hegemonic pretensions of other powers -- especially tsarist Russia, which bestrode Europe like a colossus by the time of the 1814-15 Congress of Vienna, the peace conference held at the end of the Napoleonic Wars. He thus teamed up with Klemens von Metternich, the Austrian foreign minister, to design a postwar settlement that kept the British in, the Russians out, and the French down, to adapt a famous quip about NATO. The final Vienna agreement enlarged Prussia's territory to deter invasions from both the east and the west; prevented Russia from annexing an even larger slice of Poland than it eventually did; and linked the United Kingdom to the continent by way of the Concert of Europe, an informal grouping of powers established to resolve international disputes. During the early summits, where diplomats tackled the problems of the post-Napoleonic era, Metternich conducted this orchestra, but Castlereagh played first violin. He rejoiced, as he told his prime minister, Robert Jenkinson, Lord Liverpool, in 1818, in the "new discovery in the European government . . . giving to the counsels of the Great Powers the efficiency and almost the simplicity of a single state."

Crucial to Castlereagh's conception of the European balance of power was the position of the German-speaking lands, which were largely occupied by France throughout the French Revolutionary and Napoleonic Wars but became something of a power vacuum after 1815. (Germany did not become a unified state until 1871.) As a strategically vital crossroads at the center of Europe, blessed with a large population and massive economic resources, the German-speaking lands needed to be strong enough to deter predators but not so powerful as to disturb the European equilibrium. The Congress of Vienna realized these objectives by creating the German Confederation, a loose collection of states that possessed some capacity for collective action, while keeping France and Russia as far away from German territory as possible.

Castlereagh's handling of defeated France was an exemplary lesson in diplomatic tact and moderation. Instead of rubbing salt into French wounds, Castlereagh sought to reintegrate France into the European order, supporting the country's admission to the Concert of Europe in 1818. "It is not our business to collect trophies," he wrote, "but to try . . . [to] bring back the world to peaceful habits." Napoleon himself was mystified at this leniency, and he remarked that Castlereagh had made a settlement little better than he would have received had he lost the war. But time was to prove Castlereagh's wisdom: France went on to partner with the United Kingdom in the containment of Russian expansionism throughout the nineteenth century, and London and Paris -- which were at loggerheads for much of the period between 1689 and 1815 -- have not gone to war since. The Congress of Vienna laid the foundations for an unusually peaceful century on the continent, and the Concert of Europe provided an early blueprint for the League of Nations and, eventually, the United Nations.

Despite Castlereagh's internationalism, he believed in the importance of state sovereignty. In 1815, Tsar Alexander I of Russia formed the Holy Alliance with Austria and Prussia in an effort to propagate conservative values throughout Europe and nip any new flowering of revolutionary zeal in the bud. Castlereagh dismissed the Holy Alliance as "a piece of sublime mysticism and nonsense" and refused to involve the United Kingdom in its projects. In his legendary state paper of May 1820, he went on to reject the Holy Alliance's claim to act "as a Union for the government of the world or for the superintendence of the internal affairs of other states." For Castlereagh, a balance of power, not domination by the great powers, was the proper objective.


Castlereagh's moderation was also evident in his policy toward the international slave trade. Although hostile to slavery as an institution, Castlereagh was wary of immediate unilateral action to end the slave trade, as abolitionists such as his fellow Tory politician William Wilberforce demanded. Castlereagh worried that such a move would jeopardize the United Kingdom's relations with its colonies -- the loss of the United States was still fresh in people's minds -- and "throw a source of wealth into the lap of our enemies, without effecting any one good purpose to the unfortunate objects of our solicitude." He rued the British people's misguided priorities, complaining bitterly about a public that organized meetings "in every small town and village" to discuss the slave trade -- a "minor detail," in Castlereagh's view, "compared to the settlement of and adjustment of the equilibrium of Europe."

Castlereagh sought a middle path. A brash British response, he feared, would offend France and the Iberian states, which were still heavily involved in the slave trade, whereas total passivity might allow others, such as the quixotic Tsar Alexander I, to expand their influence in the guise of humanitarian action. After the Congress of Vienna, therefore, Castlereagh continued to refuse demands for immediate military action to disrupt the slave trade and instead worked to secure great-power cooperation on eventual abolition and consensual enforcement.

That faith in diplomacy has made Castlereagh a figure of reverence for noninterventionists and multilateralists ever since. But there was a dark side to his cautious multilateralism: it permitted the sustained traffic of hundreds of thousands of enslaved Africans across the Atlantic in the early nineteenth century. In this regard, it is possible to see a shadow of Castlereagh's legacy in the international community's reluctance to intervene in places such as Bosnia and Rwanda in the 1990s.

Yet as Bew brilliantly illustrates, Castlereagh was no doctrinaire noninterventionist; he also had a more ideological and unilateralist side. When he deemed it necessary, Castlereagh was willing to act alone and unprovoked with overwhelming force. As secretary of state for war in 1807, Castlereagh approved a preventive attack on Denmark merely to stop its fleet from falling into French hands. In addition to capturing the Danish fleet, the Royal Navy's shelling killed thousands of civilians and flattened much of Copenhagen. After the attack, Castlereagh congratulated one of the British commanders for having established "the natural respect that attaches to a vigorous exertion" of power.

His penchant for international cooperation aside, Castlereagh well understood that British influence in Europe depended ultimately on the application of raw military power, both at sea and on land. Beholding the fearsome might of the Duke of Wellington's army in France in 1815, Castlereagh was elated. "What an extraordinary display of power!" he exclaimed. And Castlereagh's delight was well justified, for without these 150,000 British soldiers, who composed a third of the total allied land force in the field against Napoleon, the French would never have been driven out of Spain all the way to the gates of Paris, even as the British-subsidized Austrian, Prussian, and Russian armies approached from the east.

Despite his opposition to the Holy Alliance, moreover, Castlereagh had neither unqualified respect for the internal affairs of other states nor an indifference to contemporary intellectual trends. In fact, he was a deeply ideological man who grappled with the great political and philosophical debates of his age. He was guardedly sympathetic to the French Revolution in its early stages, finding both "much to approve, and much to condemn," but he never veered from feeling "as strongly as any man, that an essential change was necessary for the happiness and dignity of a great people, long in a state of degradation." Nevertheless, he believed in the superiority of Great Britain's constitution and its more judicious pace of political reform. As the French Revolution grew increasingly tyrannical, he defended the British process of gradual change against challenges from reactionaries and revolutionaries alike. As Bew demonstrates, Castlereagh's objection to great-power intervention in other states' domestic affairs stemmed from the fear that it would be applied one-sidedly in favor of conservatism, thus preventing the peaceful evolution of absolutist systems into constitutional ones. If, as Bew rightly claims, Castlereagh believed in "enlightenment grounded in realpolitik," then he also practiced realpolitik grounded in enlightenment.

All these themes came together in Castlereagh's approach to the question of Ireland's future, which dominated his early career (he was born in Dublin) and remained with him until his death. As the son of a major Presbyterian landowner, Castlereagh was born into the Protestant Ascendancy, which governed the island, in tandem with a British viceroy, through a parliament based in Dublin. (The majority Catholic population was excluded from participation.) As a devotee of the Enlightenment, Castlereagh was familiar with the republican argument for breaking Ireland's connection with Great Britain, and he was a staunch believer in releasing Catholics from the prejudicial and oppressive penal laws. Yet Castlereagh also grasped the bitter reality that the Irish, left to their own devices, would split along religious lines and turn against one another with pikes and pitchforks, as they had during the traumatic rebellion of 1798.

Most important, Castlereagh was determined to keep republican France out of Ireland, which both the French and the Spanish had long considered a backdoor to Great Britain. In his solution to the Irish question, therefore, Castlereagh sought to kill two birds with one stone. On the one hand, in order to mobilize Irish energies for the war against Napoleon, he sponsored the Act of Union between Great Britain and Ireland in 1800. But on the other hand, he pushed for Catholic emancipation, partly to give the Irish majority a greater stake in the new political arrangement and partly to keep them out of the French camp. King George III, however, was a rabid anti-Catholic; he thus frustrated the second half of Castlereagh's plan, and discriminatory legislation against Catholics remained in place for another three decades.

For all the method and rationality in his politics, there was something profoundly unstable in Castlereagh's personality. In 1809, as secretary of state for war, he became embroiled in a bitter dispute with Canning, the foreign secretary, primarily over where British troops should be deployed to fight Napoleon in Europe. The quarrel grew so contentious that Castlereagh challenged Canning to a duel; in the event, he wounded his colleague in the thigh. Even by the standards of the day, such behavior was eccentric and irresponsible. Likewise, Castlereagh's gruesome and unexplained suicide (by cutting his throat with a razor), in 1822 -- variously attributed to fear of exposure as a homosexual and simple insanity -- is at the very least evidence of an unsettled mind.


Castlereagh's legacy is an ambivalent one. His most famous contribution -- the settlement of the Napoleonic Wars and the creation of the Concert of Europe -- paved the way for the founding of international bodies such as the League of Nations and the UN. Furthermore, Castlereagh's approval of the preventive strike against the Danish navy in 1807 helped establish a precedent for similar operations in later years, from the British bombardment of the French navy at Mers el-Kébir in 1940 (to stop France's ships from falling into Hitler's hands) to the United States' toppling of Iraqi dictator Saddam Hussein in 2003. Some of Castlereagh's other major decisions, including his opposition to the Holy Alliance and his reluctance to use unilateral intervention to end the slave trade, prefigured the fierce contemporary debates over the limits of national sovereignty and the necessary occasions for humanitarian intervention.

Castlereagh's most important legacy, however, is rooted not in any specific policy but rather in his overall approach to the European order. Castlereagh believed passionately not only that the United Kingdom must play an active role in Europe but also that maintaining a balance of power on the continent was a paramount British security interest. For the sake of this balance, if Castlereagh were alive today, he would strongly support the defense of Poland and the Baltic states against Russian intimidation. There is also no doubt that he would support the eu's Common Foreign and Security Policy, which attempts to rally the continent in support of the collective strategic good.

Above all, Castlereagh would be deeply concerned about the current travails of the eurozone. He would find familiar the role of Germany -- weak in his own time, strong today -- as the focal point of the whole European system. He would feel vindicated in his view that Europe, or at least the continental part, needed "the efficiency and . . . simplicity of a single state." He might well keep the United Kingdom out of the new fiscal and banking union that German Chancellor Angela Merkel is trying to create, but provided he was satisfied that it posed no threat to British interests -- or at least that the dangers posed by chaos in continental Europe were far greater -- there is every reason to suppose that he would vigorously support the enterprise.

If today's European leaders want to follow Castlereagh's example, they should remake the eurozone into a single federal state and form a reinvigorated confederation with their British cousins across the channel. And if they can accomplish that, there is a good chance that the present concert of Europe, which has sounded so badly off-key in recent times, can be reborn as a melodious duo.

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  • BRENDAN SIMMS is Professor of the History of International Relations at the University of Cambridge.
  • More By Brendan Simms