Co-authored by Michael Chioke*

The outside world’s war with ISIS seems to be evolving in a more positive direction. In the battle for Kobani on the Syrian-Turkish border, ISIS fighters are retreating even although elsewhere in Syria and Iraq they are holding or advancing, for example in Iraq’s Anbar province.

It’s time to debate a further issue: how important is the caliphate project to ISIS as a fighting force? Is so-called “Caliph Ibrahim” (Abu Bakr al-Baghdadi) still a revered leader or is his prestige weakening as ISIS’s early victories turn into a protracted struggle with defeats and higher casualties. Do ISIS fighters still believe that the Islamic State caliphate will endure or are doubts emerging and morale declining? For a leader’s charisma to endure he must be seen by his people, but Abu Bakr has appeared only once, his sermon at a mosque in Mosul in which he proclaimed that he was “the One.”

Nor are other top leaders or military commanders in view, having gone underground after the capital Raqqa was hit by coalition air strikes. ISIS leaders are in peril and they are acting accordingly.

Presumably Abu Bakr has constituted a shadow government-in-waiting, to be announced at an appropriate moment under his supervision as Caliph and Supreme Leader. But the moment must be credible, i.e. Islamic State must appear to be permanent, its existence accepted by neighboring countries and outside powers. An IS regime would furthermore need a foreign policy and domestic agenda. Under Caliph Ibrahim’s authority there would be a president or prime minister and a foreign minister who would become Islamic States’ diplomatic and domestic policy faces. But so far Islamic State has no foreign policy except the gun.

ISIS/Islamic State differ from Al Qaeda in that Al Qaeda is a pure terrorist organization that didn’t try to capture territory and create a state. Its purpose was to instill fear and provoke a reckless response. ISIS in this regard resembles more the Taliban, which conquered and governed Afghanistan. Much Western debate focused on whether Osama bin Laden was an irreplaceable leader whose death or capture would cause AQ’s collapse. Bin Laden went into hiding, appearing rarely and only on video. After years on the run he was found and killed, his body dumped at sea. There was no worldwide wave of vengeance; Ayman al-Zawahiri took over without much success. A leader who is not seen eventually loses his charismatic grip on the followers. Caliph Ibrahim is facing this problem.

What would happen to ISIS as a political, military and terrorist operation if Abu Bakr were eliminated? What would happen to the dream of a resurrected Caliphate that would organize all Islam?

There are two views. The first one, the Obama administration’s, is that the war against ISIS will in any case be a long campaign. The goal (“to degrade and ultimately destroy ISIS”) will take years to achieve.

There is another hypothesis: ISIS fighting morale would collapse if the Caliph disappeared and the Caliphate lost its plausibility. Another Caliph might be named but it would most likely repeat the bin Laden/Zawahiri succession. The religious passion that animates the soul of many ISIS fighters would lose its focus and thus its implacability. Abu Bakr — we know he’s a shrewd, capable strategist — has either made contingency plans for succession or he has not. In this regard he’s in the position of any star CEO who has built a company and a brand.

Generals can be replaced with alacrity, not the Supreme Leader. The transition in Iran from Ayatollah Khomeni to Ayatollah Khameni was successful because the revolution to oust the Shah had succeeded and the new regime had ten years to construct its web of institutions, religious control of society and its secret police.

Without its chiliastic, millenarian focus, why would Islamic State fighters go on killing and terrorizing with such ferocity? If there were no caliphate project, what would make it different from other Islamist organizations fighting in one or another country? Islamic State’s distinctiveness would evaporate.

Its invincibility as a fighting force must no longer be taken for granted. It was ousted from Mosul dam, pushed off Sinjar Mountain and currently is backing away from the siege of Kobani. The conclusion is not that the latter hypothesis is true and the first mistaken. It’s that a contrarian evaluation of ISIS’s durability is increasingly plausible.

Most importantly, the two views are not mutually exclusive. They should be pursued simultaneously. War is the public battle. Off the radar screen, using Special Forces, local contacts and sophisticaled intelligence, a clandestine campaign should try to find and eliminate the ISIS/Islamic State top leadership. Abu Bakr and the others are doubtless moving all the time because they know they’re in danger. Hopefully the U.S. led coalition is already in active pursuit.

*Ronald Tiersky is Eastman Professor of Politics at Amherst College. Michael Chioke is a two-tour Afghanistan veteran, currently a senior at Amherst.