Earlier this week at Cato-@-Liberty, David Boaz posted a very useful and timely response to a Heritage Foundation view of military spending that will likely be of interest to a wide audience.

The Heritage “charticle” published in Tuesday’s print edition of The Washington Examiner, showed that military spending as a share of total government spending had fallen, and that entitlement spending consumes a larger share of the federal budget than it did three or four decades ago. But we didn’t really need fancy charts to know that. David included a few charts of his own, and closed with an important challenge. Surely, Heritage scholars wouldn’t:

suggest that U.S. national security should be measured by the relationship of military spending to entitlement spending. Surely we would agree that military spending must be sufficient to ensure U.S. security and not tied to some extraneous factor. So I invite the creators and promoters of the…chart to explain exactly what they think it proves.

Boaz also alludes to serious disagreements between some conservatives* and many libertarians about the foreign policy tradition of the Founders. David linked to a true gem from the archives—Ted Galen Carpenter’s essay on the Constitution and U.S. foreign policy from 1987. But others have written on this topic, including Justin Logan in a more recent issue of Cato Policy Report. And I discuss the historical roots of restraint in my book, The Power Problem.

As it happens, I was in Naples, Florida yesterday giving a talk on the subject, and my video discussing libertarian foreign policy was recently posted at Libertarianism.org.

In the video, and in my lecture last evening, I stressed the Founders’ deep and abiding skepticism of government, and their fears of, in George Washington’s words, “those overgrown military establishments which, under any form of government, are inauspicious to liberty.” In drafting the Constitution, James Madison aimed to prevent the new nation from acquiring such a military by limiting the federal government’s ability to wage foreign wars (through restrictions on funding for the military) and by constraining the one branch most prone to initiate war, the executive.

He saw the vesting of the war powers in the legislature, not the executive branch, to be one of the most important provisions of the entire document. Madison explained the rationale in a letter to Thomas Jefferson: “The constitution supposes, what the History of all Governments demonstrates, that the Executive is the branch of power most interested in war, and most prone to it. It has accordingly with studied care vested the question of war in the Legislature.”

Such sentiments strike many today as unnecessarily unwieldy, and perhaps even dangerous. They doubt the wisdom of having foreign policy conducted by 535 de facto secretaries of state. The world is simply too dangerous, they say; the president of the United States must have the power to initiate wars unencumbered by the doubts of the public who will actually fight them and pay for them.

There were no doubt some in the late eighteenth century who believed much the same thing. Though the Congress was much smaller then, the politics were just as nasty. Gridlock was the rule. Meanwhile, the dangers facing the dis-united states were far greater than what we confront today. But by fortunate circumstances as much as by design, a foreign and military policy founded on—in Jefferson’s immortal words from his first inaugural address—“peace, commerce, and honest friendship with all nations; entangling alliances with none,” survived and thrived in North America.

Libertarian skepticism of an activist foreign policy, particularly one that is prone to waging foreign wars, is also informed by F. A. Hayek’s observations on the “fatal conceit;” the erroneous belief that “man is able to shape the world around him according to his wishes.” (For more on Hayek’s theory as applied to foreign intervention, see this paper by Christopher Coyne and Rachel Mathers).

What Hayek called the knowledge problem also contributes to unintended consequences. These can be quite serious in the domestic context. They are more serious still in foreign policy. This is obvious when one recalls the rather banal point that wars aim to kill people and break things. Even well-intentioned wars—those, for example, that are designed to remove a tyrant from power and liberate an oppressed people—unleash chaos and violence that cannot be limited solely to those deserving of punishment. And repression and the stifling of human rights and individual liberty often occurs in the aftermath of wars that appear to have achieved their original objectives. (Just ask the people of Iraq.)

For all of these reasons—the expansion of state power, the problem of imperfect knowledge, the law of unintended consequences—libertarians should treat war for what it is: a necessary evil. “War cannot be avoided at all costs, but it should be avoided wherever possible,” writes Boaz in his seminal work Libertarianism: A Primer . “Proposals to involve the United States—or any government—in foreign conflict should be treated with great skepticism.”

Another argument that some conservatives advance in support of a crusading foreign policy abroad is that freedom needs a champion, and the United States is the only country that can play that role. People living under a tyrant’s heel must be liberated; the power of the U.S. military might convince the petty despot to step down. Failing that, the sharp end of American military power might deliver him to a prison, or the gallows.

But freedom has a champion—many, really—and it is a grave disservice to the work of institutions like the Cato Institute, the Atlas Foundation, the Institute for Humane Studies, and of countless other libertarian and classical liberal organizations to suggest that liberalism can only flourish under the covering fire of American armaments. Implicitly, calls for wars of liberation ignore or dismiss the progress toward liberty that has occurred during the past half century, and that has taken place peacefully. The U.S. role has largely been to provide a suitable model to emulate.

That was the approach favored by the Founders. Washington, in his Farewell Address and Jefferson in his First Inaugural Address both admonished their countrymen to steer clear of the internal affairs of foreign powers. Both were anxious for the United States to avoid unnecessary wars. Any claim that Washington or Jefferson secretly aspired to promote their ideas around the world by force, but were unable to do so solely because the new nation was too weak militarily, ignore that the government of the early Federal period was weak by design. A government large enough to preside over an empire of liberty would likewise be able to stifle liberty at home.

* A number of outspoken conservatives, including the editors and contributors to The American Conservative, as well as Andrew Bacevich, Douglas Macgregor and Bruce Fein, articulate a conservative, originalist interpretation of U.S. foreign policy.