Listen up, Wesley Clark! Here's how generals get elected president.

Slate's Michael Kinsley once described the early Al Gore as an old person's idea of a young person. Similarly, you might say that Gen. Wesley Clark is a peacenik's idea of a wartime candidate. It's easy to suspect that the groundswell of enthusiasm for his Democratic presidential campaign springs from the belief that he alone can risk a bold antiwar stand because his military stars would inoculate him from being Dukakis-ized. (In January, Slate's Chris Suellentrop assessed Clark.)

But to dismiss Clark's candidacy as a liberal delusion is to misread the appeal of generals as presidential candidates. The 12 generals (six of them notable) who have become president have typically won support by styling themselves not as candidates of war but as candidates of peace. *

Americans have always felt ambivalent about military leaders in politics. On the one hand, they expect their leaders never to shrink from a fight, especially in crises. During the Cold War and again since 9/11, aggressive and even martial rhetoric—summoning national loyalty, demonizing enemies, talking tough—has rarely failed to please.

Yet the public's taste for militarism has limits. The colonists' battles with the British army instilled a lasting suspicion toward standing armies, and the founders explicitly kept the military under civilian control. Isolated from Europe, America aspired, in its preferred self-image, to be a peace-loving country. (Bloody policies toward the neighboring Indians were conveniently omitted from the picture.)

It's no wonder that political generals have consistently invoked the Roman hero Cincinnatus —acting as if power is an obligation thrust upon them, not something they crave. In U.S. history, no one has been likened to the Roman hero more than George Washington, who answered the call to duty in the Revolutionary War, then returned to his farm, and then heeded the call again when the early republic sought a chief executive.

Generals since then have emulated Washington's Cincinnatus image by fashioning themselves as nonpolitical public servants, high above the fray. They have tried to get others to draft them into public office rather than advertising their ambition. In 1836 and 1840, supporters of William Henry Harrison, who had won a smashing victory in the Indian wars at Tippecanoe in 1811, called him "The Farmer of North Bend" who was reluctantly willing "to leave his plough to save his country." In 1848, Zachary Taylor, a Mexican War hero, used the slogan "Untrammeled with Party Obligations."

So it has been more recently as well. In 1948, both parties courted Dwight Eisenhower as a presidential candidate. In the mid-1990s, Colin Powell pretended to be a political independent, encouraging talk of a draft, though he eventually came out as a Republican. Today Clark—who similarly denied being a Democrat for longer than was plausible—seems to bask in the draft-Clark committees that are sprouting up. By playing Cincinnatus, Clark and other military chiefs can radiate purity and appeal to the public's distrust of power-grasping career politicians.

Clark also follows another tradition of political generals. In America, soldier-candidates typically succeed not just when they fashion themselves above petty politics, but also when, like George Washington, they use their experience in war to show how much they value peace.

Sometimes it's a tough sell. Andrew Jackson had to overcome a reputation for being brutal and dictatorial. Often compared by critics to Napoleon, he was attacked by opponents for executing six of his own soldiers as punishment after the Battle of New Orleans. But by the time he ran for president in 1828, he was 61, had served in the Senate and retired (Cincinnatus-like) to his farm, and was mellowing.

Ulysses S. Grant likewise earned a reputation during the Civil War as a ferocious commander, and critics faulted him for the many deaths his troops incurred. But his front-line achievements gave him credibility as a peacemaker, and Americans cheered his magnanimity after his victory at Appomattox. When Union soldiers in their camps began firing rounds in celebration, Grant stopped the gloating, declaring that "the rebels are our countrymen again." Three years later, when he accepted the Republican Party's presidential nomination, he enhanced his reputation for charity by ending his letter with the famous line, "Let us have peace." A policy of reconciliation was central to his candidacy.