I spent early 2011 trying to ease tensions between Syria and its neighbors. I never predicted the brutality that would come from inside.

Now and then I am asked if I had predicted, way back in March 2011 when violence in Syria began, that within a few years a quarter-million people would be dead, half the population homeless and hundreds of thousands of defenseless civilians terrorized, traumatized, tortured and starved. The companion question, more often than not, is if I had forecast the failure of the West to offer any protection at all to Syrian civilians subjected to a systematic campaign of mass homicide. Having first been exposed to Syria as a teenage exchange student, I was expected by questioners to know something about the place. And as a State Department officer, I was assumed to know something about my government.

But no. It took me the better part of eighteen months to comprehend fully the scope of an unfolding humanitarian and political catastrophe. By September 2012, when I resigned my State Department post as adviser on Syrian political transition to Secretary of State Hillary Clinton, I knew that Syria was plunging into an uncharted abyss—a humanitarian abomination of the first order. And I knew that the White House had little appetite for protecting civilians (beyond writing checks for refugee relief) and little interest in even devising a strategy to implement President Barack Obama’s stated desire that Syrian President Bashar Assad step aside. But at the beginning, nothing drawn from my many years of involvement in Syria inspired accurate prophesy.

That Russia’s recent military intervention in Syria has shocked the Obama administration is itself no surprise. For nearly two years, Washington had chased Moscow diplomatically in the belief that the Kremlin’s soothing words about supporting political transition in Syria were truthful. That which was obvious to many—Russia’s desire to perpetuate Assad in office—is now jarringly clear to the administration. That training and equipping anti-Assad rebels to fight anyone but Assad has been dropped like a bad habit by an administration warned not to proceed along these lines is hardly a bolt from the blue. But the White House is not alone in failing to accurately forecast the severity of the Syrian disaster.

The major reason for my lack of foresight: It didn’t have to turn out this way, and I remain mildly surprised that it did. It is not that Syrians were without grievances concerning the way they were being governed. Widespread unemployment, underemployment and opportunity deficits were already prompting those with means among the best and brightest to leave the country. Although the regime’s corruption, incompetence and brutal intolerance of dissent were hardly state secrets, Assad was not universally associated by Syrians with the system’s worst aspects: “If only the president knew” was a phrase one heard often. Some Syria watchers believed that the Arab Spring would visit the country in the form of political cyclone. I did not. I did not think it inevitable that Assad—a computer-savvy individual who knew mass murder could not remain hidden from view in the 21st century—would react to peaceful protest as violently as he did, with no accompanying political outreach. And as Syria began to descend into the hell to which Assad was leading it, I did not realize that the White House would see the problem as essentially a communications challenge: getting Obama on “the right side of history” in terms of his public pronouncements. What the United States would do to try to influence Syria’s direction never enjoyed the same policy priority as what the United States would say.

Back in early 2011, it seemed possible not only to avoid violent upheaval in Syria but to alter the country’s strategic orientation in a way that would counter Iran’s penetration of the Arab world and erase Tehran’s land link to its murderous Hezbollah militia in Lebanon. Much of my State Department time during the two years preceding Syria’s undoing was thus spent shuttling back and forth between Damascus and Jerusalem, trying to build a foundation for a treaty of peace that would separate Syria from Iran and Hezbollah on the issue of Israel.

There was a degree of idealism in my quest, born in the brain of an American teenager many years before. But there was another personal element as well. Long before Hezbollah murdered Mr. Lebanon—Prime Minister Rafik Hariri—in 2005, it had brutally and pathologically tortured to death a friend of mine serving as an unarmed United Nations observer, Marine Lt. Col. Rich Higgins. Peace between Israel and Syria would require Damascus to cut all military ties to Hezbollah. It would require Syria to stop facilitating Iran’s support to Hezbollah. It would set the stage for a Lebanon-Israel peace that would further marginalize Lebanon’s murder incorporated. Peace for its own sake is good. But the prospect of beating Hezbollah and its Iranian master was inspiring. This prospect, more than anything else, motivated the mediation I undertook as a deputy to Special Envoy George Mitchell in the State Department.

Assad, told me in late February 2011 that he would sever all anti-Israel relationships with Iran, Hezbollah and Hamas and abstain from all behavior posing threats to the State of Israel, provided all land lost by Syria to Israel in the 1967 war—all of it—was returned. My conversation with him was detailed in terms of the relationships to be broken and the behavior to be changed. He did not equivocate. He said he had told the Iranians that the recovery of lost territory—the Golan Heights and pieces of the Jordan River Valley—was a matter of paramount Syrian national interest. He knew the price that would have to be paid to retrieve the real estate. He implied that Iran was OK with it. He said very directly he would pay the price in return for a treaty recovering everything.

Israeli Prime Minister Benjamin Netanyahu was interested. He was not at all eager to return real estate to Syria, but he found the idea of prying Syria out of Iran’s grip fascinating. And the negative implications for Hezbollah of Lebanon following Syria’s peace accord with Israel were not lost on him in the least. Although there were still details to define about the meaning of “all” in the context of the real estate to be returned, Netanyahu, too, knew the price that would ultimately have to be paid to achieve what he wanted.

But by mid-April 2011 the emerging deal that had looked promising a month earlier was off the table. By firing on peaceful demonstrators protesting police brutality in the southern Syrian city of Deraa, gunmen of the Syrian security services shredded any claim Assad had to governing legitimately. Indeed, Assad himself—as president of the Syrian Arab Republic and commander in chief of the armed forces—was fully responsible for the shoot-to-kill atrocities. Even so, he told Barbara Walters in a December 2011 ABC TV interview, “They are not my forces, they are military forces belong[ing] to the government . . . I don’t own them, I am the president. I don’t own the country, so they are not my forces.”

Before the shooting began the United States and Israel were willing to assume Assad had sufficient standing within Syria to sign a peace treaty and—with American-Israeli safeguards in place—make good on his security commitments before taking title to demilitarized territories. But when he decided to try to shoot his way out of a challenge that he and his first lady could have resolved personally, peacefully and honorably, it was clear he could no longer speak for Syria on matters of war and peace.

Some of my U.S. government colleagues from bygone days tell me we dodged a bullet: that an uprising against the Assad regime’s arrogance, cluelessness and corruption in the middle of treaty implementation would have caused real trouble. Others believe we were too slow: that a treaty signing in early 2011 could have kept the gale force winds of the Arab Spring from unhinging Syria. I don’t know. I don’t know if Assad or Netanyahu would, in the end, have done a deal. What I do know is that I felt good about where things were in mid-March 2011. What I also know is that by mid-April hope of a treaty was gone, probably never to return in my lifetime.

Assad’s decision to apply lethal violence to something that could have been resolved peacefully was the essence of betrayal. He betrayed his country so thoroughly as to destroy it. Four years on, he reigns in Damascus as a satrap of Iran and a dependent of Moscow. In the end, he solidified Israel’s grip on land lost in 1967 by his defense minister father.

Fully complicit in the Assad regime’s impressive portfolio of war crimes and crimes against humanity, Iran relies on its client to secure its overland reach into Lebanon. And Russia works to sustain Assad as a rebuke to Washington. All the while, the eastern part of Syria is run by the self-styled Islamic State, or ISIL, itself a criminal enterprise. For the most part, the two titans of crime—the Assad regime and the Islamic State—have been able to live and let live, concentrating their hideous repertoires of violence on civilians and on armed rebels offering a nationalistic alternative to both. The result is widespread and profound hopelessness. Many Syrians are giving up on their beloved Syria. They are voting with their feet.

There is no end in sight to this vicious bloodletting. Iran and Russia could stop the gratuitous mass murder but opt not to do so. Moscow now facilitates it with military intervention. The United States could stop it or slow it down significantly without invading and occupying Syria—indeed, without stretching the parameters of military science. But it has adamantly refused to do so. Meanwhile, the minions of the Islamic State loot and destroy the world heritage site of Palmyra while subjecting much of eastern Syria to their own brand of violent rule and internal terror.

Both sides of this debased criminal-terrorist coin need to be addressed urgently. Assad’s barrel bombing of Deraa in the south—where peaceful protests against regime brutality first attracted international notice in March 2011—along with his bombing of Aleppo and Idlib in the north must be stopped cold. These horrific devices kill the innocent and recruit for the Islamic State: precisely as they are intended to do. Means exist far short of invasion and occupation to make it difficult for Assad regime helicopters to deliver their deadly cargoes. What is required is a clear statement of intent by Obama, one communicated to the Department of Defense, so that options can be produced for presidential decision and execution.

With regard to ISIL, a professional ground combat component provided by regional powers is desperately needed to work with coalition aircraft to sweep this abomination from Syria and permit a governmental alternative to the Assad regime to take root inside Syria. With central and eastern Syria free of both the regime and ISIL, an all-Syrian national stabilization force can be built. Western desires for a negotiated end to the Syrian crisis would be based, under these circumstances, on more than a wish and a hope.

The United States should neither seek nor shy away from confrontation with Russian forces in Syria. Moscow will not like it if its client’s ability to perform mass murder is impeded. Russia will not be pleased if ISIL, its false pretext for military intervention in Syria, is swept from the table. Ideally, Russia will not elect to escort regime aircraft on their mass homicide missions. And it would be difficult for even Russian President Vladimir Putin to articulate outrage if ISIL is crushed militarily. But if Russia seeks out armed confrontation with the United States in Syria, it would be a mistake for Washington to back down. People like Putin will push until they hit steel. And he will not stop in Syria.

Having failed miserably as a prophet in 2011 does not deter me from predicting the following: Obama will bequeath to his successor a problem of gargantuan dimensions if he does not change policy course now. Left to the joint ministrations of Assad and the Islamic State, Syria will continue to hemorrhage terrified, hungry and hurt human beings in all directions while terrorists from around the globe feast on the carcass of an utterly ruined state. Western Europe now reaps a whirlwind of desperate and displaced humanity it thought would be limited to Syria’s immediate neighborhood.

My failure to predict the extent of Syria’s fall was, in large measure, a failure to understand the home team. In August 2011, Barack Obama said Assad should step aside. Believing the president’s words guaranteed decisive follow-up, I told a congressional committee in December 2011 that the regime was a dead man walking. When the president issued his red-line warning, I fearlessly predicted (as a newly private citizen) that crossing the line would bring the Assad regime a debilitating body blow. I still do not understand how such a gap between word and deed could have been permitted. It is an error that transcends Syria.

I want the president to change course, but I fear that Syrians—Syrians who want a civilized republic in which citizenship and consent of the governed dominate—are on their own. I’ve been so wrong so many times. One more time would be great. It would mean saving thousands of innocent lives. It would mean real support for courageous Syrian civil society activists who represent the essence of a revolution against brutality, corruption, sectarianism and unaccountability. It would mean the reclamation of American honor. It would mean preserving my near-perfect record of getting things wrong. It would be a godsend.

Frederic C. Hof is a Senior Fellow with the Atlantic Council’s Rafik Hariri Center for the Middle East.