There is something odd about the chorus of criticism against President Obama's foreign policy. Normally, the age-old debate over military intervention revolves around a particular conflict. From WWI to the Iraq War, hawks and doves have always squabbled over the ethics, efficacy, and necessity of attacking a particular enemy at a particular time.

But Obama's critics haven't focused on any particular conflict or enemy. They speak of the peril in Syria, Iraq, Afghanistan, Iran, Ukraine, and the South China Sea. They warn of threats from Putin, Khamenei, Kim Jong-Un, Al Qaeda, Hamas, Hezbollah, the Taliban, or, more generally, dictators, fanatics, and terrorists. George W. Bush's Axis of Evil has become a Legion of Doom with new enemies, like ISIS, regularly joining the pantheon of international bad guys.

Though no single foe presents an imminent threat American security, foreign policy pundits argue that Obama's cautious foreign policies embolden our enemies and undermine international stability. Some compare his policies unfavorably to his predecessor's. Others appeal nostalgically to the days when the United States stared down the Soviet Union across the Iron Curtain. But either way, the message is the same: Obama is weak.

They do not argue that the US should attack all its enemies, of course. Most critics urge Obama to employ American military force to create a credible deterrent. The idea derives from Cold War theories of brinkmanship when the US faced down the Soviet Union in Berlin, Cuba, and other strategic theaters. After the Soviet collapse, interventionists heralded the US as a "hyperpower" that that could and should use the same deterrent effect to impose global stability. They see no limit to what we can achieve by force or threat of force if we have the will do carry it through.

But the deterrent strategy that worked against the Soviet Union has not worked against smaller regimes and insurgencies, as demonstrated by Serbia, Rwanda, Afghanistan, Syria, and Iraq (twice). In all of these cases, we have had to actually go to war to make a difference. Nor did the deterrent strategy work against such regimes during the Cold War, as we saw in Korea, Vietnam, and even the Falkland Islands.

Moreover, it was not conventional forces that spooked the Soviets. It was nukes--the imminent threat of unimaginable catastrophe. Before Hiroshima, former military powers like Germany and Japan defied US threats as brazenly as Saddam Hussein. Time and again, the US has been forced to launch massive invasions in order to defeat its opponents.

Despite American opponents' refusal to back to down, interventionists might still have a point if the US were truly the hyperpower they imagine it to be. But it is not. The history of American warfare since Vietnam has repeatedly proven that overwhelming military often fails achieve the desired end. Even the defeat of a foe does not guarantee that we can create a stable ally, as we are once again discovering in Iraq and Afghanistan.

When our military fails to achieve its goal, we actually undermine our global influence. Our bungled efforts to pacify the Middle East have underscored the obvious: The US is not a hyperpower. We have failed not because of we lack the will to succeed but because our ambitions are greater than our capabilities.

That does not mean that we're militarily impotent. As long as war endures in the world, the US may be called to fight, and we can triumph. But we must choose to fight based on a realistic assessment of the need, the cost, and the probability of success.

Few interventionists speak in such terms. Calling themselves "realists," they sermonize about global credibility, power vacuums, and national security, much as ancient imperialists once spoke of national honor and vital territory. Every war is "necessary," and the interventionists would hurl soldiers and machines like bullets at every target, then blame the pacifists when they miss and splatter on the wall.

Yet, war is almost never necessary, and it rarely achieves what its proponents promise. Obama has his strengths and weaknesses, but this at least he understands.

Michael Wolraich is the author of Unreasonable Men: Theodore Roosevelt and the Republican Rebels Who Created Progressive Politics