One of the odder aspects of present-day politics is the assumption that if you are antiwar you are on the left, and if you are conservative you are “pro-war.” Like labelling conservative states red and liberal states blue, this is an inversion of historical practice.

The opposition to America’s entry into both World Wars was largely led by conservatives. Senator Robert A. Taft, the standard-bearer of postwar conservatism, opposed war unless the United States itself was attacked. Even Bismarck, after he had fought and won the three wars he needed to unify Germany, was staunchly antiwar. He once described preventive war, like the one America is being pressured to wage on Iran, as “committing suicide for fear of being killed.”

Conservatives’ detestation of war has no “touchy-feely” origins. It springs from conservatism’s roots, its most fundamental beliefs and objectives. Conservatism seeks above all social and cultural continuity, and nothing endangers that more than war.

In the 20th century, war brought about social and cultural revolutions in the United States, including a large-scale movement of women out of the home and into the workplace. Nineteenth-century reformers had labored successfully to make it possible for women (and children) to leave the dark satanic mills and devote their lives to home and family, supported by a male breadwinner. The Victorians rightly considered the home more important than the workplace. A man’s duties in the world of affairs were a burden he had to carry to provide for his household, not something women should envy.

This happy situation was overturned in both world wars as men were drafted by the millions while the demand for factory labor to support war production soared. Back into the mills went the women. The result was the weakening of the family, the institution most responsible for passing the culture on to the next generation.

The threat war poses to the cake of custom is exacerbated by one of its foremost characteristics: its results are unpredictable. Few countries go to war expecting to lose, but wars are seldom won by both sides. The effects of military defeat on social order can be revolutionary.

Russia’s involvement in World War I gave us Bolshevism. Germany’s defeat made Hitler possible. As the First World War shows, if a conflict is costly enough, the victors’ social order can suffer nearly as badly as that of the vanquished. Not only did the British Empire die in the mud of Flanders, but postwar Britain was a very different place from Edwardian Britain.

The plain fact is, conservatives loathe unpredictability. They also know that vast state expenditures and debts can destabilize a society, and no activity of the state is more expensive than war. America’s adventure in Iraq, driven in no small part by the quest for oil—which will now mostly go to China—has already cost a trillion dollars, with another trillion or two to come caring for crippled veterans. Even the peacetime cost of a large military can break a country, as it broke the Soviet Union. American conservatives used to be budget hawks, not warhawks.

If we look beyond dollars, francs, pounds, and marks, the toll of war grows endless. After World War I, there were no young men on the streets of Paris. As one British observer noted, the German casualty lists from the early battles in that war read like the Almanach de Gotha, the book that catalogued the German nobility. Most frighteningly to conservatives, wars like World War I can destroy a whole culture’s faith in itself. It may well be that European civilization’s last chance for survival was a German victory on the Marne in 1914.

One gain that comes out of war is as disturbing to conservatives as any of the losses: an aggrandizement of state power. The argument of “wartime necessity” runs roughshod over all checks and balances, civil liberties, and traditional constraints on government. In the 20th century, American progressives knew they could only create the powerful, centralizing federal government they sought by going to war. It was they, the left, who engineered America’s entry into World War I. Nearly a century later, 9/11 gave centralizers in the neocon Bush administration the cover they needed for the “Patriot Act,” legislation that would have left most of America’s original patriots rethinking the merits of King George. Just as nothing adds more to a state’s debt than war, so nothing more increases its power. Conservatives rue both.

When Edmund Burke, generally regarded as conservatism’s 18th-century founder, was faced in Parliament with a proposal for a war to ensure the river Scheldt in the Austrian Netherlands remained closed so Antwerp could not compete with London, his response was, “A war for the Scheldt? A war for a chamber pot!” That was a genuinely conservative reaction.

Real conservatives hate war. If that now sounds as strange as thinking of blue as the conservative color, we can thank a bunch of (ex?)-Trotskyites who stole our name, and a military-industrial-congressional complex that has bought right and left alike. If history is a guide, and it usually is, the price for the nationalist right’s love of militaries and war is likely to be higher than we can to imagine.

William S. Lind is director of the American Conservative Center for Public Transportation and author of the Maneuver Warfare Handbook.