After five years of war, terrible tragedies, and undeniable crimes by Syrian President Bashar al-Assad and his backers, it is hardly surprising to hear calls for more U.S. action: punitive strikes against the regime, a no-fly zone, and increased arms for the opposition, all with the ultimate goal of Assad’s departure. These demands are not new, but now with the battle for Syria’s second-largest city of Aleppo coming to a head, further reports of chemical weapons use, and the coming November presidential elections the calls from longstanding critics and former administration officials will surely grow louder. One assumption, however, has gone largely unchallenged: that forcing Assad’s violent removal will help end the war.

Proponents of greater action argue that increased pressure will force Assad to negotiate his own departure, but, thus far, escalation against the regime has only led to counter-escalation. Assad’s obstinacy is unlikely to change as long as he is being asked to negotiate his own political suicide—especially given that the major alternative, his opposition in the northwest, is largely radicalized and hardly a viable option for Syria’s future. Assad is emboldened knowing that the West has neither a plan, nor even the right pieces, to rebuild the country in his wake.

Since at least spring 2015 (and arguably earlier), the more moderate elements of the opposition have been entangled with radical ones. Most notable among these is Syria’s al-Qaeda affiliate, Jabhat al-Nusra. (Now rebranded Jabhat Fatah al-Sham, it denies maintaining links with al-Qaeda, though the relationship certainly remains intact.) Seemingly moderate and radical groups have coordinated militarily and shared weapons and supplies through formal coalitions and informal arrangements. The opposition’s main backers in the Gulf and Turkey have not limited their support to those who resist working with radical groups, allowing the problem to grow.

Though Western audiences typically single out Nusra and ISIS as Syria’s extremist groups, the radicalization within the opposition runs far deeper. More Western-conscious groups within the chimera of Islamist militias, ones that are arguably the most powerful forces in the opposition, have made attempts to present themselves as “Salafist-lite” by memorizing and regurgitating the right talking points on moderation and pluralism in Syria, but they are hardly moderates. The differences between these groups and “genuine extremists” like Nusra seem to be more a matter of public relations than true ideological divergence.

For example, Ahrar al-Sham, which lacks formal ties with al-Qaeda, nevertheless has had close links to its central leadership and even vocally models itself after the Taliban in Afghanistan. Ahrar al-Sham, Jaish al-Islam, and others have been accused of committing war crimes, and in July, Nour al-Din al-Zenki, which had previously been deemed “moderate” and received U.S. support, beheaded a 12-year-old Palestinian whom it accused of fighting for Assad. Critics often decry Assad and Russia for conflating all of the rebels as “terrorists,” but they fail to address the very real radicalization that permeates the opposition landscape.

Make no mistake, Assad bears a great deal of responsibility for Syria’s radicalization, thanks not only to his war crimes, but also to his releasing extremists from Sednaya prison early in the war to taint the opposition. But it would be foolhardy to deny that this radicalization is a reality.

A Post-Assad Syria

If the West did commit sufficient military force to violently oust Assad, perhaps the regime’s supporters would fall by the wayside. Hezbollah may well abandon Syria, Iraqi militias would likely return home to fight ISIS there, and Iranian and Russian forces might depart once they no longer have a regime to support. Iran would likely continue to provide weapons and aid to the remnants of Assad’s loyalist forces to maintain its connection to Syria, but its influence and involvement would be severely diminished.

Yet Assad’s downfall would nonetheless lead to long-term chaos and an entirely new set of challenges. The West would struggle to rebuild the country with a radicalized and fragmented opposition that, post-Assad, would no doubt turn against itself. This “war after the war” would result in a Syria dominated not by a central authority or even regional governments, but instead by militia rule, not unlike Libya or Afghanistan.

From Nusra to the “Salafists-lite,” powerful hardline groups (whose legitimacy the West should not recognize) would dominate the weaker moderate groups and carve Syria into miniature fiefdoms. Warlords would either clash over territory and patronage networks, or if confronted by the West or secular forces in Syria would likely unite to resist central governance and the rule of law. Such infighting may generally be less intense than Syria’s first five years of war, but would likely last for decades.

Furthermore, though these militias claim not to have objectives beyond Syria, they would likely cooperate with organizations that do have transnational objectives. Like groups in Afghanistan and Libya similarly unhindered by central governance, they would likely provide safe haven, training, weapons, and recruits. This would present a serious problem to both the region and the West.

How then, in the midst of a fractious, radicalized militia landscape, can the West ensure the success (or even the survival) of genuine moderates? Analysts like Charles Lister, a senior fellow at the Middle East Institute, argue that by more aggressively arming these moderates, Washington can empower them to fight extremists like Nusra and other hardliners. This is overly optimistic. Though Lister has only called for increasing the flow of weapons to vetted FSA groups, the opposition is so entangled that additional arms for the FSA will inevitably find their way to the more powerful radical militias. And if, in a post-Assad Syria, moderate FSA groups do decide to oppose these Salafists, it is unlikely they would emerge victorious. Any weapons given to perceived moderates would fall in and out of the wrong hands for decades to come.

Supporting the moderates from afar—by means of weapons and supplies, training camps in Turkey and Jordan, close air support, and limited special operations forces on the ground—will likely be insufficient to ensure their victory or their adherence to centralized democratic governance. Building new state institutions from the ground up in such a chaotic environment will be equally implausible. Instead, in a post-Baathist Syria, occupation may well be necessary to hold the country together.

Earlier this year, Saudi Arabia, Turkey, Qatar, and the UAE indicated they would contribute ground troops to Syria, but there is no reason to believe such commitments (if even carried out) would be anything more than symbolic. The United States and Western allies would need to carry the mantle of occupation. Such an operation may well require troop levels comparable to the Iraq war (about 180,000 at the height of the surge, and that still wasn’t enough). These troops could be dragged back into the conflict in Iraq, and Western forces would again become a target for foreign fighters drawn from across the region. Even if the American public had the appetite for this, there is no guarantee that such an occupation could produce a moderate Syria with strong enough institutions to stand on its own.

In an ideal world, Syria would be rid of Assad. Perhaps this could still happen under the right conditions, but Washington would need to convince the opposition’s main backers in the Gulf to push for more realistic goals: namely, allowing for a longer transition for Assad’s departure and accepting that existing state apparatuses will stay in place should the regime make constitutional reforms. Were this the case, Russia and Iran would perhaps be willing to eventually force Assad out of power in order to end the war in a way that preserves their interests, but this must be pursued diplomatically and over time. Escalating the war and violently removing Assad will have terrible consequences that will be measured not in years, but in decades.