A man holds a girl who survived what activists said was heavy shelling by forces loyal to Syria's President Bashar al-Assad in the Douma neighborhood of Damascus June 16, 2015. (Reuters)

Recent Assad regime reverses on Syrian battlefields have revived Obama administration fears of “catastrophic success:” that the person told by President Barack Obama in August 2011 to step aside might instead be pushed aside and that his fall could entail a regime collapse exploited by extremists intent on avenging the mass homicide atrocities of the regime. Notwithstanding Iran’s evident determination to do what it takes to prop up its client in a western Syrian mini-state, Western concerns about President Bashar al-Assad falling “too soon” have policy implications which, if addressed improperly, can perpetuate regime crimes against humanity that work to the benefit of the Islamic State (ISIS or ISIL) and lead inexorably to the precise outcome officials fear.

For Syrians who for years have been on the receiving end of regime criminality, it is no doubt infuriating to see the reality of an ongoing holocaust trumped in Western policy circles by fears of a possible abomination accompanying the fall of a heartlessly cynical and brutal regime. For 12 million Syrian victims of regime atrocities the argument that Assad provides some kind of stabilization service is bewildering. For Syria’s neighbors—awash in refugees—the open-ended continuation of refugee-producing murder and mayhem can hardly be attractive.

Imagine how articulated fears about Assad “leaving the wrong way” are processed by those who have begged the West for protection, only to be told that their plight does not rise to the “never again” standard; that the absence of United Nations Security Council consensus and the primacy of a nuclear deal with Iran render them unqualified for protection by parties having the ways and means to provide it. Imagine the credibility of the US “train-and-equip” recruiting pitch to nationalist Syrian rebels: pay no attention to those who drop barrel bombs on hospitals, schools, mosques, and bakeries—come help us fight ISIL while we entreat Moscow and Tehran to support political transition in Syria.

No one who had the privilege to attend the July 15, 2015 photo exhibit of Assad regime prison atrocities—a program organized by the United States Holocaust Memorial Museum in partnership with the Senate Committee on Foreign Relations and the House Foreign Affairs Committee—will lose much sleep about the prospective passing of a regime with a Hitler-like penchant for cataloguing its atrocities. No one who saw the photos taken by former Syrian military police photographer “Caesar” or listened to the testimony of a regime torture survivor will exhibit anxiety about the departure of a dictator who has authorized the unthinkable and unspeakable.

Yet concerns voiced about civilian protection issues occasioned by a regime implosion are not groundless. The Assad-Makhluf clan and its senior employees have operated in a manner consistent with their cardinal belief: no Assad, no Syria. By using military, intelligence, and private criminal assets led by and consisting largely of Alawites to wage a war of terror against mainly Sunni Muslims, they have deliberately sought to make hostages of all Alawites and of all Syrian minorities as a general matter. Through barrel bombs, starvation sieges, torture, rape, and pillage they have implanted in minority communities a fear of vengeance; fear designed to bind these minorities to the survival of a regime that steals from them while sacrificing their children.

The result is that large scale acts of vengeance victimizing innocent civilians cannot be ruled out if the fall of the regime—the family and its inner circle of enforcers—creates a security vacuum. It is not at all clear that the departure of a corruptly incompetent clan would have such an effect. Yet the response to this challenge simply cannot be one of Western action or inaction, tacitly supporting Iranian efforts to keep the mass murder machine in place and well oiled. As long as that machine functions, ISIL will have a recruiting case to make to desperate Syrians. As long as the machinery of industrial scale homicide keeps humming, the peril to those held hostage by the regime will increase.

Civilian protection in a post-Assad era requires civilian protection now. Otherwise, Assad will continue to incite and inflame sectarian hatreds through a multifaceted policy of collective punishment. He audaciously counts on Western inaction as the means by which the West—focused as it is on ISIL—will eventually be forced to ally itself with him. He and the pseudo-caliph share the objective of being the last two parties left standing in Syria.

As noted previously in MENASource, throwing sand into the gears of Assad’s mass killing machine is not the same thing as invading and occupying the country. It is not even tantamount to crippling his armed forces. Still, steps taken to stop the barrel bombing would be noticed. They would be noticed by a Syrian military told by Assad since day one of the Syrian crisis that the West, under current management, was not something to be feared. The effect of preventing regime helicopters from delivering their deadly cargoes could have ripple effects of tsunami strength, well beyond the regime’s rotary wing assets. It would be the clearest possible signal to the Syrian military officer corps that the regime-sustaining free ride for Assad is over.

It is for this reason that immediate diplomatic engagement with Iran on the issue of Syrian civilian protection is merited. The message from Secretary of State John Kerry to his counterpart, Foreign Minister Mohammad Javad Zarif should be stark: stop the barrel bombing or we will. Given the possible multiplier effect of a sand-in-the-gears operation and the fact that Iran has little interest in most of the places being barrel bombed, the message might resonate, thousands of lives may be saved, and the military option might be set aside. But time is of the essence. Too much of it has already been wasted.

The worst course of action would be inaction. To do nothing will have major negative consequences. To avoid taking steps—diplomatic for sure, military if necessary—to protect Syrian civilians from Assad regime mass terror is to promote extremism and to imperil those Assad has taken hostage. Failure to protect Syrian civilians is the policy equivalent of endorsing Assad’s strategy: a strategy that kills the innocent, shames the West, and facilitates the work of ISIL. Only through inaction in the face of this real, ongoing outrage can fears of Assad “leaving the wrong way” receive the ultimate form of validation: the fulfillment of a bad dream.

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