Most Wars in U.S. History Were Not Needed to Protect National Security Domestic economic and political factors have been an important cause of most major U.S. wars.1 Personal and political costs to politicians usually decide whether most wars happen.2 Bueno de Mesquita best summed up the general phenomenon: "International relations is, simply put, a venue for politicians to gain or lose domestic political advantage."3 Similarly, another academic study concluded that American wars are usually undertaken for domestic political reasons, not out of national security necessity.

In national security terms, most U.S. wars were risky and may have even been counterproductive. This book will examine the origins of major American wars, looking for lesser-known domestic causes, which were often decisive in provoking or causing war. When most historians look back at the casus belli of American wars, they focus on the "threats" that led to conflicts. But history does not support this claim. Even early in its history, the continental United States, with its enviable geographic isolation, was so far away from the world's center of conflicts and foreign powers that it was difficult for any major adversary to project any use of effective military power against it. Later, in the mid-twentieth century, the United States was the first nation to develop a large arsenal of nuclear weapons, which made it suicidal for any nation to attack or invade it.

This intrinsic natural security and later devastating weaponry raise doubts that most U.S. wars have had much national security value or were initiated to protect the U.S. people and mainland from harm. At America's founding, even most European powers with overseas empires or territories and powerful navies posed only a limited threat to Americans, who are protected by two huge oceans, extensive shorelines, and a vast, rugged interior. Over time, because overseas threats became manageable, Americans focused on their "manifest destiny" to extend the U.S.

government's rule to the North American West Coast. This domestic-focused and self-serving doctrine devised by American elites entailed displacing the weakened or distracted the European powers, Spain and France, which then held territory in the Western hemisphere; annihilating the technologically inferior native peoples, who also succumbed in vast numbers to European-introduced diseases; and taking advantage of two empires, Britain and Russia, whose home countries were far away.