Any such campaign of sectarian cleansing would shape the entire region in new ways. Assad would likely rely on the shabiha, Alawite militias supported by Hezbollah and the Iranian Revolutionary Guards, to carry out his oppression; over the course of the war, these militias have proven more reliable than Syria’s traditional security agencies at laying siege to opposition-controlled pockets in Syria. (The shabiha have already been used to displace — and, the opposition alleges, massacre — Sunni Syrians in Homs and the adjacent Orontes Valley.) In other words, Syria would be drawn into deeper alliances with Iran and Hezbollah. In response, Sunni countries in the region would probably try to support a continued Sunni insurgency — even if that meant relying exclusively on jihadists with their own agendas.

The upshot: Iranian and Hezbollah forces will probably remain in Syria indefinitely, permanently institutionalizing what had originally been an ad hoc arrangement. And the foreign-supported Sunni insurgency, mired in a stalemate with Assad, would likely begin to focus on international terrorism. It is unlikely that Syria’s secular opposition would find an amenable home in these ungoverned spaces; those who manage to evade torture or death at the hands of the Assad regime would try to form their own enclaves, or join the waves of refugees forced into exile.

There is also the question of how Assad would try to repair Syria’s destroyed economy. According to a study by the Syrian Center for Policy Research, total losses of the war are estimated at $85 billion, $40 billion in the first quarter of this year alone. The Syrian regime has burned through a lot of the estimated $17 billion in hard currency reserves it held at the beginning of the uprising, to compensate for combined U.S., EU, and Arab League sanctions on Syrian oil production — measures that are unlikely to be lifted even if Assad holds on.