What's the most powerful political force in the world? Some of you might say it's the bond market. Others might nominate the resurgence of religion or the advance of democracy or human rights. Or maybe it's digital technology, as symbolized by the Internet and all that comes with it. Or perhaps you think it's nuclear weapons and the manifold effects they have had on how states think about security and the use of force.
Those are all worthy nominees (no doubt readers here will have their own favorites), but my personal choice for the Strongest Force in the World would be nationalism. The belief that humanity is comprised of many different cultures -- i.e., groups that share a common language, symbols, and a narrative about their past (invariably self-serving and full of myths) -- and that those groups ought to have their own state has been an overwhelmingly powerful force in the world over the past two centuries.
It was nationalism that cemented most of the European powers in the modern era, turning them from dynastic states into nation-states, and it was the spread of nationalist ideology that helped destroy the British, French, Ottoman, Dutch, Portuguese, Austro-Hungarian, and Russian/Soviet empires. Nationalism is the main reason the United Nations had fifty-one members immediately after its founding in 1945 and has nearly 200 members today. It is why the Zionists wanted a state for the Jewish people and why Palestinians want a state of their own today. It is what enabled the Vietnamese to defeat both the French and the American armies during the Cold War. It is also why Kurds and Chechens still aspire to statehood; why Scots have pressed for greater autonomy within the United Kingdom, and it is why we now have a Republic of South Sudan.
Understanding the power of nationalism also tells you a lot about what is happening today in the European Union. During the Cold War, European integration flourished because it took place inside the hot-house bubble provided by American protection. Today, however, the United States is losing interest in European security, the Europeans themselves face few external threats, and the EU project itself has expanded too far and badly overreached by creating an ill-advised monetary union. What we are seeing today, therefore, is a gradual renationalization of European foreign policy, fueled in part by incompatible economic preferences and in part by recurring fears that local (i.e., national) identities are being threatened. When Danes worry about Islam, Catalans demand autonomy, Flemish and Walloons contend in Belgium, Germans refuse to bail out Greeks, and nobody wants to let Turkey into the EU, you are watching nationalism at work.
The power of nationalism is easy for realists to appreciate and understand, as my sometime collaborator John Mearsheimer makes clear in an important new paper. Nations -- because they operate in a competitive and sometimes dangerous world -- seek to preserve their identities and cultural values. In many cases, the best way for them to do that is to have their own state, because ethnic or national groups that lack their own state are usually more vulnerable to conquest, absorption, and assimilation.
Similarly, modern states also have a powerful incentive to promote national unity -- in other words, to foster nationalism -- because having a loyal and united population that is willing to sacrifice (and in extreme cases, to fight and die) for the state increases its power and thus its ability to deal with external threats. In the competitive world of international politics, in short, nations have incentives to obtain their own state and states have incentives to foster a common national identity in their populations. Taken together, these twin dynamics create a long-term trend in the direction of more and more independent nation-states.
Obviously, nations and states don't always reach the goal of a unified "nation-state." Some nations never succeed in gaining independence, and some states never succeed in creating a unified national identity for themselves. And not every cultural or ethnic group thinks of itself as a nation or aspires to independence (though one can never be sure when some group might begin to acquire "national consciousness" and head in that direction). Nonetheless, the past hundred years has seen a steady rise in the number of states and the emergence of strong national movements in many of them, and I see no reason to expect this trend to be reversed.
Once established, a nation-state is a self-reinforcing phenomenon. Nation-states are hard to conquer and subdue, because the local population will usually resist outside invasion and continue to struggle against a foreign occupier. Successful national movements tend to spawn imitators, leading to further demands for statehood. Despite its occasional shortcomings (and the obvious examples of "failed states" like Somalia, Yemen, or Afghanistan), the national state is likely to remain the most important political entity in world politics for the foreseeable future.
Because American national identity tends to emphasize the civic dimension (based on supposedly universal principles such as individual liberty) and tends to downplay the historic and cultural elements (though they clearly exist) U.S. leaders routinely underestimate the power of local affinities and the strength of cultural, tribal, or territorial loyalties. During the Cold War, we persistently exaggerated the strength of transnational ideologies like Communism, and underestimated the degree to which national identities and interests would eventually generate intense conflicts within the Marxist world. Osama bin Laden made the same mistake when he thought that terrorist attacks and video-taped fulminations would ignite a mass movement to re-establish a transnational Islamic caliphate. And anyone who thinks that a rising China is going to tamely submit to U.S. or Western notions of the proper world order fails to appreciate the degree to which nationalism is also a central part of the Chinese worldview, and far more important than any lingering "communist" ideals.
Unless we fully appreciate the power of nationalism, in short, we are going to get a lot of things wrong about the contemporary political life. It is the most powerful political force in the world, and we ignore it at our peril.