Syrian President Bashar Assad winning the Syrian civil war is akin to dying of a heart attack, but a Syrian opposition victory is the equivalent of dying from cancer. Unfortunately, the time for preventive medicine was more than three years ago.
There's a conceit in Washington that holds that debates can continue endlessly and that the rest of the world will remain frozen in time until a decision is made. The reality, of course, is that the world revolves neither around the White House nor Congress. While intervention in Syria might have tipped the balance against Assad in the first weeks of conflict, it was not long before both Assad's foreign allies came to his rescue and the opposition radicalized. Politicians and partisan, meanwhile, cling stubbornly to positions hashed out when the Syrian civil war was in its infancy.
Arming the opposition was never wise. Most of those with whom U.S. engages diplomatically have no control over ground in Syria. Even if moderates – for the sake of argument, let's define them as those who do not engage in cannibalism – outnumber radicals, numbers mean less than dedication to the fight. Moderates might defect to the radicals or be conquered by them, losing their weaponry in the process. Think the Islamic State in Mosul.
Nor does the opposition simply want guns and ammunition; rather, they seek a qualitative military edge – for example, surface-to-air missiles, drones and tanks. Whatever proponents of direct assistance say, the U.S. government has little proven capacity to vet accurately: If U.S. officials could not figure out what two Chechen brothers in Boston were up to, how can they realistically claim to have the ability to vet those speaking no English and living in a war zone? It would be foolish to trust the Syrian opposition with such technologies and assume no blowback.
There are exceptions to direct military support: The Syrian civil war is not simply a clash between regime and Islamists. The Kurds have carved out "Rojava," an autonomous area in northeastern Syria where girls go to school, women walk in the markets, and municipalities continue such basic services as trash pickup. This Kurdish area is so secure that it now hosts tens of thousands of Christian refugees and an even great number of Sunni Muslim refugees. How sad it is that out of deference to Turkey, the Obama administration boycotts the only stable, secular zone remaining inside Syria.
That said, it would be wrong to suggest that the only choice America had was between arming the opposition and doing nothing. To return to the medical analogy, President Barack Obama acted like a doctor who diagnosed cancer at stage one, but refused to prescribe any medicine, even as it metastasized to stage four. Arming the opposition may not have been wise, but direct military action could have been. Had the United States imposed a no-fly zone, the Syrian Air Force might not have been able to drop barrel bombs on civilians and Iran might have been unable to fly in advanced weaponry and Revolutionary Guardsmen. And had U.S. forces targeted extremists, the Islamic State might not have grown to the point where it not only threatens to consume Syria and Iraq, but Jordan and Lebanon as well. It's the case of the road not taken.