The Ukraine crisis, as German Chancellor Angela Merkel recently remarked in the German parliament, really is a conflict between two worlds. On the one hand are the "postmodern" politics of the twenty-first century, the world of negotiations, compromises, and treaties. On the other hand is the world of classical power politics, whose rules are clearly paramount for Moscow. For Germany, there is more at stake here than for many other nations. German security, German freedom, and German prosperity are tied to the precondition of postmodern politics. In a world of pure power politics, Germany would be at a major disadvantage.

Germans abandoned power politics in 1945. Germany's total defeat was the moment at which the country abandoned everything that it had upheld for years: thinking in terms of war, conquest, and destruction. The new Germany was to be a better Germany, purged of militarism and aggression. The country's internal disposition had its external equivalent: a geopolitical environment in which the United States assumed foreign and security policy on behalf of a defeated Germany. West Germany was founded as a socioeconomic entity under a U.S. security umbrella. Only with great reluctance would the country yield to calls for rearmament.

Today, Germany is the paradigmatic postmodern state. It has transformed its considerable economic potential not into military strength, as great powers do, but into prosperity and the construction of the EU. The EU itself is also a postmodern entity: a mesh of treaties and institutions whose strength lies not in the availability of battalions-hard power-but in the willingness of its members to recognize the EU's legal order. Conflicts are dealt with through communication, and diverging interests are evened out through compromise. In the short term, that is often arduous, but in the long term, it has been very successful.

As a postmodern state, Germany has created this congenial environment together with its European partners. Unlike countries such as France, however, Germany very much depends on such a postmodern environment. Germany can prosper only when the logic of power politics is superseded on the international stage by the logic of international and transnational cooperation. And only to the degree that strength is exercised in terms of economic power, and not capacity and readiness for war, is Germany an influential player on the world stage.

By contrast, in a Hobbesian world in which states permanently eye each other with the aim of finding their opponents' weaknesses and then scrupulously exploiting them, a world in which stronger states subjugate weaker ones, Germany in its specific disposition would have a hard time. Germany needs a circle of friends that keep the country at arm's length from the conflicts of this world. It needs the fabric of international law, treaties, and secure borders. And it needs a protector that stands ready in case of emergencies to deploy nuclear weapons to deter attackers.

Yet Germany's most important partners, the United States, France, and Britain, have only one foot in the postmodern world of treaties and economic cooperation. At the same time, they have retained the defining attributes of traditional great powers: nuclear weapons and effective, tried-and-tested armies. If push came to shove, they could defend themselves alone. Germany could not. Germany needs a world order in which basic principles are respected by all key players.

It is in Germany's eminent interest to strengthen and promote the existing postmodern world order. The more the principles of international law are respected and the more decisively international law and integrated economies trump classical power politics, the safer Germany is. But whenever the principle of "might makes right" prevails, Germany is on the losing side.

It is therefore in Germany's interest to react especially sensitively to Russia's aggression toward Ukraine. The annexation of Crimea by military means and the current threat of force along Russia's border with Ukraine are massive attacks on the principles of international law as enshrined in the UN Charter. The attack on Ukraine is an attack on the very order that underpins Germany's freedom, security, and prosperity. If international relations really are falling back into the logic of military aggression and territorial expansion, then alarm bells should be ringing in Germany.

Europe is at a crossroads. Either it will succeed in beating back the attack on the basic principles of Europe's peaceful order and thus breathe new life into these principles. Or we are moving toward a logic akin to the one that prevailed in the decades before 1945: a world in which military strength determines nations' fate in their battle for survival. In such a world, Germany would face the choice of either becoming a classical power again, as between 1871 and 1945, or letting itself be pushed around by other powers, essentially losing sovereignty and autonomy.