It's not that Americans are disinterested in foreign affairs, it's that their interest is finely calibrated. The issues must matter to Americans, so most issues must carry with them a potential threat. The outcome must be uncertain, and the issues must have a sufficient degree of clarity so that they can be understood and dealt with. Americans may turn out to have been wrong about these things in the long run, but at the time, an issue must fit these criteria. Afghanistan was once seen as dangerous to the United States, its outcome uncertain, the issues clear. In truth, Afghanistan may not have fit any of these criteria, but Americans believed it did, so they focused their attention and energy on the country accordingly.

Context is everything. During times of oil shortage, events in Venezuela might well have interested Americans much more than they did last week. During the Cold War, the left-wing government in Venezuela might have concerned Americans. But advancements in technology have increased oil and natural gas production in the United States. A left-wing government in Venezuela is simply another odd Latin government, and the events of last week are not worth worrying about. The context renders Venezuela a Venezuelan problem.

It is not that Americans are disengaged from the world, but rather that the world appears disengaged from them. At the heart of the matter is geography. The Americans, like the British before them, use the term "overseas" to denote foreign affairs. The American reality is that most important issues, aside from Canada and Mexico, take place across the ocean, and the ocean reasonably is seen as a barrier that renders these events part of a faraway realm. Terrorists can cross the oceans, as can nuclear weapons, and both can obliterate the barriers the oceans represent. But al Qaeda has not struck in a while, nuclear threats are not plausible at the moment, and things overseas simply don't seem to matter.

Bearing Some Burdens

During the Cold War, Americans had a different mindset. They saw themselves in an existential struggle for survival with the communists. It was a swirling global battle that lasted decades. Virtually every country in the world had a U.S. and Soviet embassy, which battled each other for dominance. An event in Thailand or Bolivia engaged both governments and thus both publics. The threat of nuclear war was real, and conventional wars such as those in Korea and Vietnam were personal to Americans. I remember in elementary school being taught of the importance of the battle against communism in the Congo.

One thing that the end of the Cold War and the subsequent 20 years taught the United States was that the world mattered — a mindset that was as habitual as it was reflective of new realities. If the world mattered, then something must be done when it became imperiled. The result was covert and overt action designed to shape events to suit American interests, perceived and real. Starting in the late 1980s, the United States sent troops to Panama, Somalia, Bosnia, Kosovo and Kuwait. The American public was engaged in all of these for a variety of reasons, some of them good, some bad. Whatever the reasoning, there was a sense of clarity that demanded that something be done. After 9/11, the conviction that something be done turned into an obsession. But over the past 10 years, Americans' sense of clarity has become much more murky, and their appetite for involvement has declined accordingly.

That decline occurred not only among the American public but also among American policymakers. During the Cold War and jihadist wars, covert and overt intervention became a standard response. More recently, the standards for justifying either type of intervention have become more exacting to policymakers. Syria was not a matter of indifference, but the situation lacked the clarity that justified intervention. The United States seemed poised to intervene and then declined. The American public saw it as avoiding another overseas entanglement with an outcome that could not be shaped by American power.

We see the same thing in Ukraine. The United States cannot abide a single power like Russia dominating Eurasia. That would create a power that could challenge the United States. There were times that the Ukrainian crisis would have immediately piqued American interest. While some elements of the U.S. government, particularly in the State Department, did get deeply involved, the American public remained generally indifferent.

From a geopolitical point of view, the future of Ukraine as European or Russian helps shape the future of Eurasia. But from the standpoint of the American public, the future is far off and susceptible to interference. (Americans have heard of many things that could have become a major threat — a few did, most didn't.) They were prepared to bet that Ukraine's future would not intersect with their lives. Ukraine matters more to Europeans than to Americans, and the United States' ability to really shape events is limited. It is far from clear what the issues are from an American point of view.