Before Germany’s reunification in 1871, the central German foreign policy debate was how to achieve it — what was called the “German question.” Leftists and revolutionaries favored a republican Großdeutschland including Catholic Austria. Liberals and conservatives pointed out that its Habsburg monarchy, which would likely have endured, even in a limited, constitutional role, also ruled over non-Germans, including Croats, Hungarians, Italians, Romanians and Slovaks. Such a “Greater Germany” would not be a nation state and inherently unstable. They favored a Kleindeutschland instead, one that was dominated by Protestant Prussia.

Under the Prussian chancellor Otto von Bismarck, the “Lesser German solution” was pursued. Bismarck was a hardened aristocrat with little regard for democracy and a proponent of realpolitik. He alternately allied with Austria, waged war on Austria, waged war on France, allied again with Austria as well as Russia, broke with Russia, allied with Italy and mended fences with Russia to preserve a favorable balance of power in Europe and prevent a Franco-Russian alliance from rising against Germany.

The country’s third and last emperor, Wilhelm II, abandoned Bismarck’s balance of power policies in favor of expansionism. He fired the “Iron Chancellor” and failed to renew the Reinsurance Treaty with Russia that had guaranteed neutrality in case either side would engage in a war with a third party. Like Hitler later, Wilhelm favored an alliance with Britain instead to prepare for a civilization struggle he foresaw between Teutons and Slavs.

Historian Fritz Fischer argued, somewhat controversially, in Griff nach der Weltmacht: Die Kriegzielpolitik des kaiserlichen Deutschland 1914-1918 (1961) that Wilhelmine Germany deliberately acted on the assassination of the heir presumptive to the throne of its ally Austria, Archduke Franz Ferdinand, in 1914 to achieve territorial expansion in Mitteleuropa.

The idea of a Mitteleuropa originated with the nineteenth century Romantic writer Constantin Frantz who proposed a Central European confederation to unite Austria and Prussia. Frantz rejected the liberal nation state, which Bismarck would turn into a conservative project, and called for a commonwealth instead that comprised Belgium, the Netherlands, Poland and Switzerland, one that could balance against both Britain’s empire and Slavic Russia, which he considered the bigger threat.

Liberal politician Friedrich Naumann built on Frantz’ thesis in his 1915 book Mitteleuropa which advocated not the integration, rather the subjugation of Central and Eastern Europe by ethnic Germans who had settled across what are today the Baltic states, Poland, Romania and Ukraine in a Drang nach Osten. Friedrich Ratzel, a geographer, had legitimized the conquest of these territories when he argued in 1901 that states should be allowed to expand “organically” to accommodate population growth and the German people needed Lebensraum to the east.

This introduced the notion of a Germany that was historically changeable on the map. Ratzel saw territorial expansion as a sign of the nation’s vitality. That was view was echoed in Oswald Spengler’s Der Untergang des Abendlandes (1918-1922) which warned of the imminent decline of Western civilization as a result of corrupting bourgeois influences and a lack of cultural vitality. The book was a sensation in Germany, despite unfavorable academic reviews.

World War I general and academic Karl Haushofer mixed Ratzel’s Lebensraum thesis and Spengler’s feared civilizational decline to argue in 1935 that the state had a duty to safeguard “not only the land within the frontiers of the Reich but the right to the more extensive Volk and cultural lands.” Like Spengler, he saw urbanization as a symptom of national decline because it diminished birthrates and a people’s mastery of the soil.

These theories informed the ethnic and foreign policies of Adolf Hitler’s National Socialists. Hitler saw little value in urban industry and trade which would have required a maritime orientation. Rather he foresaw the acquisition of vast agricultural lands in Eastern Europe to satisfy the needs of an autarkic and expansive Germany. The reintegration of ethnic Germans living there — a policy called Heim ins Reich — was, for the Nazis, not the end goal, as it had been for many pan-Germanists during the interwar period, but the beginning of a struggle for Eurasian domination that should have produced a Greater German Empire stretching from the Netherlands into the Ural Mountains.

Poland was the strategic linchpin for these ambitions as it provided both a buffer between Germany and the Slavic lands to the east and a gateway to domination over Ukraine and other parts of Southeastern Europe. Hence Germany’s refusal to recognize an independent Poland in the 1918 Brest-Litovsk peace treaty it signed independently with Russia and Hitler’s invasion in 1939 that set off World War II.

Germany’s foreign policy orientation changed dramatically after its defeat in the Second World War. East Germany was denied a foreign policy of its own, being reduced to a Soviet satellite state. West Germany was occupied by the Western powers and quickly became America’s most loyal ally on the European continent.

The Franco-German rapprochement that defined postwar Europe was not only a wish of West German leaders but a geopolitical necessity. Their country amounted to little more than the Rhine Confederation that had been a client state of France’s in the early nineteenth century. Without the former Prussia, withering behind the Iron Curtain, and the ability to balance its relations with Russia against the Atlantic powers, Germany’s only recourse was to become an Atlantic power itself.

The first break came when Chancellor Willy Brandt launched his Ostpolitik in 1969. Despite French apprehension about improved relations between the two Germanys and American worries that Brandt would reach an accommodation with the Soviet Union at the expense of the Western alliance, what this normalization of ties achieved was not domination or surrender but restored influence and détente.

It was also a harbinger of things to come. Following the dissolution of the Soviet Union in 1991, Germany similarly conducted a conciliatory foreign policy toward countries it had once aspired to conquer.

Former American national security advisor Zbigniew Brzezinski argued in The Grand Chessboard (1997) that Germany, by then “safely anchored in Europe and rendered harmless but secure by the visible American military presence,” could promote the rehabilitation of Central European states whose economic and political progress had stalled during the half century of Russian domination. “It would not be the old Mitteleuropa of German imperialism,” he wrote, “but a more benign community of economic renewal stimulated by German investments and trade.”

Such a community has since come about with the inclusion of Central and Eastern European states in the European Union and NATO, their memberships sponsored by Germany.

The critical breakthrough was provided in 1990 when Germany finally recognized the Oder-Neisse line as its border with Poland, putting to rest any lingering Polish fears of future German territorial claims. Through its alliance with Poland, Germany’s influence extends further eastward, into the Baltic states and Ukraine.

German reunification that same year also spelled the end of the Franco-German parity that had kept Germany “European” throughout the Cold War. Instead, Europe looks increasingly “German” as the country’s central geographical position on the continent as well as its economic heft makes it the only power capable of leading the European Union.

Yet for the first time in its history, Germany is reluctant to accept such domination even when few of its neighbors are alarmed by the prospect.