Maybe, just maybe, the world leaders who gather in Vienna this weekend to discuss Syria will, against all odds, find some breakthrough that moves the world one step closer to a peace deal ending Syria's war. It's hard to argue that it's not at least worth the jet fuel to fly there to try. But no one is particularly optimistic, and there is a one-word answer for why: Assad.
In theory, at least, the major parties in Vienna agree on a lot of the basics. They want to end the fighting, they want to get rid of ISIS and al-Qaeda, they want an end to sectarianism, and they want political reform. But they can't agree on what to do about Syrian leader Bashar al-Assad.
It's not that Assad is himself so crucially important. But he is at the middle of a fundamental disagreement over Syria's future, one to which there is, as yet, no clear middle ground. The question of whether he stays or goes has become a question about the degree to which Syria does or doesn't return to the pre-war status quo, and right now the major parties of this war just can't agree on that.
Syria's opposition, after years of enduring Assad's barrel bombs and chemical weapons, and the forced disappearances and torture chambers before them, have said over and over they could never accept that Assad stay in office.
The US, too, has repeatedly insisted that Assad must go, correctly concluding that Assad and his policies are such a driver of sectarianism that he makes the country ungovernable and that peace is simply impossible while he remains in office. Sunni states in the region that fund the opposition, such as Turkey and Saudi Arabia, would also require that Assad leave power.
The two big question marks, then, are Russia and Iran, Assad's two foreign backers who are deeply involved in the war and who would thus need to agree to any peace deal in order for it to work. It is just not clear that they would be willing to part with him.
It is not the case that Russian and Iranian leaders care especially about Assad or what happens to him. Moscow and Tehran are not committing hundreds of their own to fight in Syria as some sort of gift to their buddy Bashar. Rather, they're fighting in Syria to protect their national interests. They believe that keeping Assad in power is necessary to protecting those interests. And they might be right.
The fundamental dynamic of the Assad regime, since it took power in the 1970s, has been minority rule: the Alawites, at times supported by other religious minorities such as Druze and Christians, rule over the country's Sunni majority. That dynamic was never stable, and it was maybe only a matter of time until it collapsed, violently or not.
Iran, an officially Shia nation, does not support Assad so much out of religious comity — while Alawites consider themselves Shia, many Shia consider them heretics — as out of strategic interests that happen to line up with sectarianism. Since at least the early 2000s, Iran has been in a growing struggle for regional influence with Saudi Arabia and other Gulf Sunni states. While it was never inevitable that the Middle East would come to split along Sunni-Shia lines, that is its status today. As a result, Iran believes that it needs an Alawite government in Syria to retain its influence there, for which it gets not just a strategically placed ally against the Sunni powers, but also a buffer against Israel and a land route by which to arm anti-Israel groups in Lebanon and Gaza.
Iran thus fears, with good reason, that if Assad falls, he will be replaced by a Sunni government (Syria, after all, is mostly Sunni) that will align with the other Sunni states. Iran would not just lose a crucial ally, it would likely gain yet another adversary in the region. That is why it is fighting so hard to keep him lodged in power.
It is possible to imagine a scenario in which Iran might accept Assad's departure, as long as Tehran had a guarantee that it would maintain its strategic interests in Syria. But Iran can only know that for sure if Syria's government remains sectarian and Alawite-led. But that would mean merely changing the face of the regime without changing its character. And it would require denying Syrians the right to democratically elect their own government. That would likely be unacceptable to the opposition, and it's hard to imagine the rebels putting down their arms in such a scenario.
Maybe there is a possibility for something like Lebanon's 1989 Taif Agreement, which helped end the country's civil war by establishing a government that is democratic but that also enshrines government roles based on religion and ethnicity (for example, the prime minister must be Sunni and the president Christian) so that those groups have a fair say. But Syria's demographics make this harder: The population is about three-quarters Sunni. It's difficult to imagine a Taif-style agreement that would satisfy Sunnis that the era of sectarian rule was over, while sufficiently empowering Alawites as to satisfy Iran that their interests would be protected.
Again, it comes back to Assad, or at least someone like him. Iran currently seems all but certain to reject any deal whereby its interests are not guaranteed. But those interests are pretty substantial: Iran wants a Syria that is aligned with it and against both Israel and the Gulf Sunni states. The only sort of Syrian government that seems likely to deliver this is one ruled by Alawites — by people like Assad who will need Iran's support.
Russia is easier. It, too, is in Syria in large part to protect its interests there (as well as to further other goals). That means a Syrian government that is pro-Moscow and that will allow Russia to keep its military bases there — its last remaining ally outside of the former Soviet sphere. Unlike Iran, though, Russia does not need the Syrian government to be sectarian and minority-rule in order for it to get what it wants. There is no reason a Sunni-led Syria could not maintain military basing deals with Russia.
It's not going to be easy for Moscow to agree to full elections and democracy in Syria, knowing that many Syrians identify Russia as aligned with the hated Assad regime, and given that Russia is currently bombing Syrian rebels. Still, it is not impossible to imagine the opposition agreeing to a peace deal that grants Russia certain concessions, or promising that Alawites will retain senior defense positions, thus allowing Russia to keep its contacts in the Syrian military.
Some in the US government believe, for this reason, that Moscow isn't just bluffing when it says that it would accept Assad's departure. And they believe, with reason, that Moscow could give in on the larger and more important question of retaining Alawite minority rule. But even if Iran gives up Assad — which it currently has shown no sign of seriously considering — there is every reason to believe that it would insist on replacing him with someone else just like him.
The American strategy, at this point, appears to be one primarily of diplomacy and pressure: diplomacy to find and exploit any glimmer of an opening or a common ground, and pressure to try to compel Russia and Iran to conclude that further fighting in Syria won't win them anything, so they should cash out now and accept whatever compromises are necessary for a peace deal.
That strategy has the merits of neither worsening the violence nor costing any American lives. But Russia and Iran have both already demonstrated they are willing to endure terrible costs in Syria to prop up Assad. It is not clear that anything the US is willing to do (or maybe even can do) will convince Iran and Russia that they are better off cutting their losses.
The question hanging over Vienna, then, is in many ways the same question that began the war: whether Syria will retain Assad-style minority Alawite rule. The answer to this, from both Iran and the Syrian opposition, is definitive, categorical, and mutually exclusive. There is no obvious middle ground, and thus there is every reason to believe that they will continue fighting. And as long as they are both fighting, the war will drag on.