As Americans see images of New Hampshire-born journalist James Foley beheaded by members of the extremist militant group known as the Islamic State in Iraq and the Levant (ISIL), some commentators insist that the current chaos is a direct result of President Obama’s reluctance to intervene decisively in the multi-year conflicts in Iraq and Syria. Most notably, Obama’s own former Secretary of State, Hillary Clinton, in an interview with The Atlantic’s Jeffrey Goldberg, suggested that Obama’s failure to aid the Syrian rebels led to the rise of ISIL.

Clinton claims “that the failure to help build up a credible fighting force of the people who were the originators of the protests against Assad … left a big vacuum, which the jihadists have now filled.” Inherent in that statement is the belief that there was a cadre of relatively liberal-minded opponents of Bashar al-Assad’s regime inside of Syria, and that American support would have been the decisive factor in ensuring that they would triumph over both Assad and the ISIL extremists. By this logic, if the United States had chosen to arm the “correct” anti-Assad rebels in Syria, we would not now be bombing ISIL in Iraq.

Experts aren’t so sure. George Washington University Professor Marc Lynch concludes, “Had the plan to arm Syria’s rebels been adopted back in 2012, the most likely scenario is that the war would still be raging and look much as it does today, except that the United States would be far more intimately and deeply involved.”

And who, exactly, we were supposed to arm was never clear. When former U.S. Ambassador to Syria Robert Ford praised recent gains by Syrian moderates, he mentioned only one group by name: “the Army of Islam, led by an ambitious Islamist commander named Zahran Alloush.” But the University of Oklahoma’s Joshua Landis has shown that Alloush might not be so moderate after all.

The debate over what we should have done with the Syrian rebels back in 2012 also largely ignores the fact that the United States and its allies apparently did offer a good bit of training, resources, and weapons to purportedly moderate Syrian fighters who were vetted for their supposed democratic leanings.

But, somewhere along the line, the screening process failed. “Washington and its allies,” concludes Souad Mekhennet in The Washington Post, “empowered groups whose members had either begun with anti-American or anti-Western views or found themselves lured to those ideas in the process of fighting.”

“First I fought under what people call the ‘Free Syrian Army’ but then switched to [the Al-Qaeda-linked terrorist group] Al Nusra. And I have already decided I will join the Islamic State when my wounds are healed,” one of these fighters explained. “Sometimes I joke around and say that I am a fighter made by America.”

This phenomenon of training people, and then later fighting them, isn’t new. And yet, the certainty of those who claim that early action to arm the Syrian rebels would have produced a better outcome reflects the interventionist bias so prevalent in Washington.

Even many on the political right, skeptical as they are of intervention to deal with most domestic problems, have a curious affinity for intervention when it comes to foreign ones. This a dramatic departure from the right’s intellectual forefathers who advised that “masterly inactivity” is often preferable to action for action’s sake. The same government that conservatives and libertarians don’t trust to deliver the mail or health care to the American people is somehow expected to flawlessly deliver liberty and prosperity around the world, including in places that have never known either.

To be sure, intervention might be warranted when the objective is less grandiose, and consistent with the properly narrow role of government: namely, to protect citizens against threats to their persons or property. Driving Al Qaeda from its safe haven in Taliban-held Afghanistan in October 2001 certainly qualifies. So, too, the targeted use of force that led to the killing of Osama Bin Laden in Pakistan in May 2011. Both operations had broad public support because they delivered a tangible security benefit at relatively low cost.

But the burden of proof properly falls on the advocates of military intervention, especially when those interventions are likely to turn into costly and protracted wars, and when the benefits are murky, at best. The interventionists must first show that the threat is sufficiently grave that it warrants addressing in the first place. And then they must explain why and how the use of force is more likely to achieve their goals than alternative courses of action.

The advocates for U.S. military intervention have an additional hurdle to clear. Having shown that the threat merits attention, they must also show that it can not be handled by others, or by non-military means. As David Boaz explains in his seminal book, Libertarianism: A Primer, “War cannot be avoided at all costs, but it should be avoided wherever possible,” thus, “Proposals to involve the United States—or any government—in foreign conflict should be treated with great skepticism.”

Sadly, such skepticism is not much in evidence in Washington. Beltway insiders continue to call for more intervention, dismiss evidence that might undermine their case, and condemn those who advocate prudence and restraint. So long as the interventionists continue to dictate the conduct of U.S. foreign policy, we can be certain that we will remain embroiled in costly and counterproductive wars. And we will consistently miss opportunities to advance U.S. security through other means.