American interest, American blood.

• Author: Merry, Robert W.
• Position: The Realist - US foreign policy

In this year's campaign debate over foreign policy, something was missing-the intertwined elements of American interests and American blood. In the rhetoric of President Barack Obama and Republican challenger Mitt Romney, seldom did we see rigorous analysis about the country's true global interests and how much citizen blood we should expend on behalf of those interests. We got vague pronouncements about American exceptionalism, using American power to salve the wounds of humanity, the pacifying effect of spreading democracy, the necessity of America's global dominance and the need to thwart anti-Western terrorists.

But there was little talk about how these missions actually would affect the lives of Americans, the global balance of power or U.S. security. There was even less talk about the appropriate price, in terms of American lives, to be paid for these missions. And yet this ultimately is any president's crucial foreign-policy decision matrix--how he or she defines the country's vital interests and how that squares with the ultimate cost.

As Germany's Otto von Bismarck, that cold-eyed realist of the nineteenth century, once remarked, "Anyone who has ever looked into the glazed eyes of a soldier dying on the battlefield will think hard before starting a war."

This is not to say that citizen blood is too precious to be spilled in pursuit of national interests. Many of our presidents heralded as among the greatest expended plenty of American blood on behalf of American interests. But it's wrong to send young soldiers to their deaths for causes unrelated to serious national interests. Bismarck captured this when he predicted in 1888--with remarkable prescience--that the next great European war would be ignited in the Balkans. Yet he insisted those lands weren't "worth the bones of a single Pomeranian grenadier." Germany had no strategic interests there worthy of German blood.

In our time, the lack of clarity about U.S. strategic goals in the post-Cold War era has spawned all kinds of mushy thinking about what our role in the world should be and what circumstances justify U.S. intervention abroad.

Consider President Obama's actions in Libya. Much has been written about the obfuscation that attended the United Nations debate--focused as it was on protecting Benghazi civilians from mass killings by the forces of Libyan leader Muammar el-Qaddafi, when the actual goal was the elimination of Qaddafi's regime. It's a worthy critique. But...