The Challenge of Avoiding War

F or scholars and practitioners alike, few tasks are more important than understanding why wars happen. Wars, to paraphrase Martin Luther or Benito Mussolini, turn the wheels of history—they can catapult states to power or topple them into the ash heap of history. But as long as there have been wars, there have been disagreements over their causes. To quote the writer Svetlana Alexievich, “War remains, as it always has been, one of the chief human mysteries.”1 Perhaps the unpredictability, complexity, and occasional inscrutability of wars’ origins make structuralist explanations for them so appealing. The roots of realism lie in the contemplation of warfare. Thucydides, that Greek font of classical realism, reacted to the Peloponnesian War; Machiavelli to the Italian wars of the Renaissance; E.H. Carr, Hans Morgenthau, Raymond Aron, and other foundational scholars of “modern” realism to the horrors of World Wars I and II. Through the wide aperture of systemic international political theory, wars are the consequence of disruptive shifts in the distribution of international power. This is a simple and powerful idea—but it is not entirely persuasive, as evidenced by the enduring debates within realism and between realism and other schools of international relations theory, to say nothing of the gap between the worlds of academia and policymaking. After all, conflict has not accompanied all power shifts. This suggests that power shifts and wars do not have to go hand in hand. War, in other words, is avoidable. For experts who watch changes to the relative distribution of international power, it has been apparent for decades that a power shift is underway. However, it was not until around the 2008 global financial crisis that this shift became undeniable—the People’s Republic of China had emerged as a serious rival to the United States. An idea which had quietly percolated within both states for years, that they were on an ineluctable