By all accounts, defeating Islamist terrorism and countering Iran will be very high Middle Eastern priorities of the Trump administration. Indeed, in the context of Syria Mr. Trump himself has spoken of supporting Russia and its Assad regime client in their 'fight' against the Islamic State. Yet such a search for common ground with Moscow in Syria will face three challenges: (1) Russia and its partners (Iran and the Assad regime) are not fighting ISIS; (2) by relying on mass homicide to put down a Syrian nationalist rebellion, Russia and its allies are, in fact, recruiting for ISIS; and (3) to collaborate with Russia and the regime is to consign western Syria – and maybe all of it, in time – to Iran.

No doubt the bewildering complexity of chaos in Syria begs for clarity and simplification. One fixed point since the beginning of the 21st century has been the President of the Syrian Arab Republic: Bashar al-Assad. The 2011 peaceful uprising against Assad's incompetent, corrupt, and violent misrule and his murderous response led to a proliferation of armed rebel groups and vacuums of governance most successfully filled by ISIS. With Assad as the one fixed point it has been natural for people to think that he and his allies are at war with everyone not accepting his rule.

In the case of ISIS, however, the relationship between Assad and the self-proclaimed "caliphate" has been largely one of live-and-let-live. Their relationship is symbiotic.

ISIS sees Assad as a recruiting bonanza: the product of a minority group who has clung to power mainly though Sunni-centric collective punishment involving mass homicide, medieval detention techniques, state-of-the-art torture recorded with Nazi-like thoroughness, starvation sieges, and the occasional old-fashioned door-to-door rape and pillage. 

Assad, on the other hand, views ISIS as the gift that keeps on giving. Its exotic, reality TV-style executions make industrial strength regime terror seem quaintly old-fashioned. Its mass casualty forays into Europe make some of what passes for European leadership long for the old days of largely invisible state terror in pre-war Syria. ISIS enables Assad to say, in effect, "You think I'm bad? Look at them!"

Moreover, ISIS has proven to be the practical key to the political survival of the Assad clan and entourage. When Russian President Vladimir Putin – after considering Iran's request for help and carefully assessing the talk show nature of Obama administration policy in Syria – decided to intervene military to save Assad, he used 'fighting ISIS' as his public diplomacy alibi.

Fifteen months later the Russian record is clear: with absolute impunity it has targeted Syrian civilians – taking special aim at hospitals – and even Syria rebel units trained and equipped by the United States for anti-ISIS operations. Moscow knows the value of a living, breathing ISIS to its hapless (if currently triumphant) client: it has left the 'caliph' to Kurds, Americans, and others, concentrating instead on saving a regime that opened Syria to ISIS in the first place.

For Iran this has been a policy windfall. Even as it builds a Hezbollah-style parastatal structure in Syria as an insurance policy, it today relies on a supplicant Assad to do as it wishes to support the original Hezbollah in Lebanon: the jewel-in-the-crown of Iran's strategic reach; an organization that threatens Israel with rockets and missiles while retaining full capabilities for worldwide terror operations.

As it focuses on the problem of Islamist terrorism in Syria and beyond, the Trump administration will have the opportunity to do things its predecessor chose only to talk about. Within the Obama administration there is no shortage of people who understand that bad, illegitimate, dignity-destroying governance (whether in Syria, Iraq, or elsewhere) is the Garden of Eden for ISIS and other extremists. Yet in Syria an administration prone to speaking endlessly about the criminal, ISIS-inspiring, state-destroying mass murder of the Assad regime decided in practice to give it a free pass, while pursuing a desultory military campaign against ISIS personnel in Syria. In Syria, the Obama administration decided, for reasons rooted in fear and uncertainty, to ignore the underlying cause of ISIS and focus instead – quite inefficiently- on the ISIS body count.

The new administration will, no doubt, review and revise what has passed for a military campaign against ISIS in central and eastern Syria. The key question however is what, in the Syrian context, President Trump will do about the two principal malign influences he has identified in the Middle East: ISIS and Iran. Once he has mastered the salient facts of the Syrian crisis, will he continue with policies and polemics in western Syria that embolden Russian adventurism in the region and beyond, facilitate the hegemonic designs of Iran, and help make the propaganda case for ISIS in Sunni Muslim communities around the world? These are the things the Obama administration has, quite unintentionally, succeeded in doing.  The United States can, under new management, do much better.

Frederic C. Hof, director at the Atlantic Council's Rafik Hariri Center for the Middle East, served as a special adviser for transition in Syria at the State Department in 2012.

More In Commentary