For decades political scientists made much of the fact that most wars in history have been fought between autocratic states: monarchies, empires, dictatorships. Democracies—states with governments responsible to their peoples—appeared in the ranks of belligerents comparatively seldom.
Seeking a reason for this, the political scientists proposed that people are less likely to vote themselves into war than autocrats are to order their people into war. Democracies have to say, "Let's us go to war," while autocrats can say, "Let's you go to war." In democracies the decision makers have their own skins in the game; in autocracies the decision makers don't.
This argument is plausible. But other things were involved. The first is the historical circumstance that democracies have been rare until recently. And so it’s no surprise they were rare among history’s belligerents.
Another confounding factor is that the spread of democracy in the 20th century was accompanied by other developments that discouraged war. The explosion in the number of democracies after 1945 occurred amid an unprecedented expansion of world trade. Countries that trade with each other think twice about going to war with each other. Only foolish vendors shoot their customers; only foolish customers shoot their vendors.
The rapid spread of democracy was also accompanied by the spread of nuclear weapons. Wars became so potentially destructive that no sane leader of any country—autocracy or democracy—would choose it as a matter of policy.
Americans weighing the theory of the democratic peace might reasonably object that even in the mostly pre-democratic era of the 19th century, one of that period's most devastating wars was between two democracies: the United States of America and the Confederate States of America. A variant of the democratic-peace theory allows that while democracies might sometimes go to war with autocracies, they almost never go to war with each other. The American Civil War is an embarrassing counterexample; beyond that, the variant is statistically almost tautologous. Given the historical scarcity of democracies, the chance that two would meet in war was about the same as finding two left-handed catchers in the same baseball game.
The nonvariant version suffers from the additional fact that the world's oldest large democracy—the United States—has been at one form of war or another more often than any other country during the two-and-a-half centuries since 1776. Americans fought Britain for eight years in the 1770s and 1780s. They fought France in an undeclared naval war in the 1790s. They fought Britain again in the 1810s, Mexico in the 1840s, themselves in the 1860s and Spain in the 1890s. Meanwhile they were almost constantly at war with Indians on the western frontier. In the 20th century, besides World War I and World War II, Americans fought in Korea, Vietnam and the Persian Gulf. And American military forces invaded nearly every country of Central America and the Caribbean, some more than once, not to mention the Philippines and Lebanon. American troops have been at war for all but two years of the 21st century, in Afghanistan and Iraq.
Some of America's wars and military interventions have been justified; others were dubious. But collectively they suggest that democratic-peace theory doesn't apply to the foremost example of democracy in world history. Indeed it fails spectacularly.
If anything, democracy in America might have made American military actions more likely. Americans often went to war in the name of democracy. Sometimes, most notably during the world wars, the justification was sincere and fitting. In other conflicts—against Mexico, against Spain, against the Indians, in the Philippines, in most of the interventions in the Western Hemisphere, in Korea, in Vietnam, in the Persian Gulf, in Iraq, in Afghanistan—democracy was either a distant hope or a thin cover for land grabbing or power projection.
Yet this very discrepancy explains much of the appeal of the theory of the democratic peace to Americans. Against the evidence, it permits the belief that in American history, peace is the norm and war the exception. There have been lots of exceptions, to be sure. But war isn’t the essence of America; war isn’t who we are.
So we tell ourselves. It’s a comforting thought.
History tells a different story.
I confess I can't document my assertion about the U.S.being at war more than other countries since 1776. And I don't really need to say it was the MOST often at war to make my larger point. Yet I think it is quite plausible. You mention Britain and France. But between 1815 and 1914 they were largely quiescent in Europe. Expanding their empires in Africa and Asia entailed sporadic violence. After 1945, they struggled briefly to hold their empires but soon gave up the cause. As for Russia, yes it expanded across Eurasia, but reached its greatest extent by the end of the 19th century. It fought against Japan, and had a civil war, and the two world wars, and the war in Afghanistan. And then Georgia and now Ukraine. It's a close call with the U.S., but Russia never sent troops so far from home as the U.S. did. As for the McDonald's theory, it's a good one as far as it goes. It underlines the importance of global trade in calming world affairs. I favor it as an explanation more than the democratic peace idea. But McDonald's first non-American store came in 1967, so it's a short run of history for a broad theory.
Another terrific essay by Prof. Brands. However, I wonder if the U.S. is truly a democracy. I'm a third-party voter and feel that we're really a plutocracy. In a true democracy, like in many Western European countries, one would have federally financed elections with limits on campaign expenses. I recently read that in the U.S., the average winner in a senatorial race shucks out $20 million (or at least his/her supporters do). Congressional races are cheaper; the winner spends an average of $2 million on campaigning.