Turkey has conducted its “Operation Olive Branch” military incursion into Syria in concert with the Free Syrian Army, which has helped Turkish forces take control of several villages in the Afrin region.

This is an uncomfortable development for U.S. policymakers because both the Kurds and Free Syrian Army were considered battlefield allies of the United States in the war against the Islamic State, and the FSA was seen as the model white-hat rebel group when the Obama administration and intervention-minded Republicans were desperately seeing “moderate” forces in the Syrian rebellion to support.

In fact, as recently as last spring, Senate Armed Services Committee Chairman John McCain (R-AZ) strongly urged increased support for the Free Syrian Army as part of the U.S. strategy for stabilizing Syria while holding the regime of dictator Bashar Assad at bay.

McCain has long been prominent among those convinced the Free Syrian Army was America’s best bet for a terrorist-free moderate rebel group to arm and support, a step he felt the Obama administration was much too reluctant to take while Russia was busy shipping arms to the Syrian regime.

He made a surprise visit to the Turkey-Syria border in 2013 to meet with FSA leaders who wanted American heavy weapons, up to and including anti-aircraft weapons, and American air support against FSA adversaries such as Hezbollah. At the time, the FSA claimed to be running perilously low on munitions, which does not seem to be a problem now that they are fighting on Turkey’s behalf against the Kurds.

McCain has not responded well to contrary arguments about the FSA, as when he reportedly stormed out of the room during a 2014 presentation by Syrian Christians who said there were Islamist fighters among the FSA’s ranks.

There was a good deal of confusion surrounding support for the Free Syrian Army in the Obama administration, which occasionally seemed uncertain about what kind of support it was sending them. Critics complained effective support for moderate rebel groups was announced too late, after too much dithering, and was delivered too long after it was finally announced. The aid program that eventually materialized was an unserious disaster.

Whether reluctantly as with Obama, or eagerly as with McCain, plans for zero-footprint Syrian intervention kept circling back around to the Free Syrian Army, despite persistent warnings it contained some unlovely people and outright terrorists. One reason for this default support is that many of the other options for American support were Kurdish groups or members of Kurdish-dominated umbrella organizations, which was problematic because U.S. policymakers wanted to avoid conflict with the Turkish and Iraqi governments. Going all-in on the Kurds would inevitably bring accusations that America was supporting Kurdish nationalists, separatists, or terrorists (as Turkey would have it).

To this very day, Turkey denounces American support for the Kurds as direct support for terrorists, no different in principle from shipping arms to the Islamic State, which is something the Turks also charge America with doing when they are especially upset. It may come as some small consolation to know that everyone involved in the Syrian quagmire accuses everyone else of supporting terrorism, and they quite frequently have a point, since even the better rebel groups have been known to cooperate with powerful terrorist forces like al-Qaeda’s Nusra Front from time to time. It is difficult for outside powers to be certain that a weapon given to a white-hat moderate rebel today will not be handed over, voluntarily or involuntarily, to a terrorist or war criminal tomorrow.

In a 2013 profile of the Free Syrian Army, the BBC noted it was a “loose network of brigades rather than a unified fighting force,” with very little operational control exercised by appealing and high-minded spokesmen like Brigadier General Salim Idris.

Brigades aligned with the Free Syrian Army and its spinoff organizations retained “separate identities, agendas and commands.” The BBC noted that some of them “work with hardline Islamist groups that alarm the West, such as Ahrar al-Sham, and al-Qaeda-linked jihadists.”

Deutsche Welle recalls that, a few weeks ago, a delegation from the Free Syrian Army came to Washington and argued that if the CIA did not resume military aid frozen by the Trump administration, its “moderate” forces would have no choice but to look elsewhere for support. Virtually overnight, the FSA signed up with Turkey to work as mercenaries in its war against the Syrian Kurds, which DW notes is difficult to square with the FSA’s nominal mission of battling the tyranny of Bashar Assad on behalf of the Syrian people. It also argues against viewing the FSA as the kind of staunch moderate ally who can be entrusted with American weapons as they fight a noble battle to liberate Syria from cruel dictatorship.

“The Free Syrian Army practically doesn’t exist,” DW quotes Mideast expert Kamal Sido telling a German broadcaster. “The Free Syrian Army is a smokescreen hiding various names, and if you look at the names, at these groups’ videos, you’ll find they are radical Islamist, Jihadist groups.”

Charles Lister of the Brookings Institution contributed the observation that nearly 80 distinct factions now identify themselves with the FSA brand, and while some are moderate in outlook, others are hardline Islamist radicals. The group as a whole is moving inexorably into the orbit of radicals, and Islamist patrons like Turkey’s Erdogan, simply because they tend to be better-armed and more ruthlessly effective on the battlefield.

If such groups ever succeeded in overthrowing Assad, they would likely either replace him with an Islamist tyranny or turn their guns against their erstwhile moderate allies – which is essentially what the FSA is doing to the Syrian Kurds right now. At this point, with Russian and Iranian support firmly behind Assad, his ouster seems unlikely, so the “rebels” are largely fighting for concessions at the negotiating table and perhaps a degree of autonomy to run their own little fiefdoms within postwar Syria. Every proposal to arm Syrian groups must carefully consider what those groups actually intend to fight for.

It should also consider how they fight. Syrian Kurds are protesting the brutality of the Turkey-FSA invasion of Afrin, which threatens to push even further into Syria, as President Erdogan has openly called for American troops to get out of his way.

Over the weekend, video footage surfaced that appears to show Free Syrian Army fighters fondling and abusing the corpse of a female Kurdish fighter killed in the Afrin operation. One of them described the woman’s body as “the spoils of war from the female pigs of the PKK,” which is the violent Kurdish separatist organization in Turkey. The Turks insist that all Syrian Kurdish militia forces are allied with the PKK, including those directly supported by the United States.

The Free Syrian Army high command promised to investigate the incident and hold those involved accountable, “if it is verified in accordance with Sharia law and our principles.” The use of Islamic law to decide whether clearly heinous activity constitutes a war crime is not what the Western world should be looking for in a “moderate” ally.

Conversely, the Turks and their allies accuse the Kurds of fighting dirty and allying themselves with the brutal Assad regime, and Kurdish forces have been blamed for civilian deaths from a rocket barrage that struck a refugee camp near the Turkish border on Monday.

Syria is a bloody mess, and white hats are hard to find, but the hellish conundrum is that failure to intervene unleashed a refugee wave that threatens to drown Europe, not to mention a humanitarian disaster within Syria that should be utterly intolerable to the civilized world. The Free Syrian Army clearly is not the easy answer that so many people have so desperately wanted it to be for the past five years. They proved it by joining a Turkish operation that may soon put the lives of American troops at risk and threaten the future of NATO.