A "political solution" in Syria-or any war-is meaningless unless the armed forces fighting accept it.

The framework for a political settlement in Syria, recently negotiated by the United States, Russia, Iran, and regional players in Vienna, is superficially impressive. It calls for a ceasefire, the establishment of a transitional government in six months, and new elections in 18 months. It does not specify which members of the Syrian armed and political opposition can participate in the process, however, or offer much incentive to make the most powerful groups want to do so. That is the main reason why it will fail to end the Syrian Civil War. The idea that international actors, all of which support local armed proxies but none of which have decisive military forces of their own on the ground, can impose a settlement on powerful warring groups without involving them in the discussion is baffling. Yet that is what this framework agreement proposes to do. It requires the external parties to agree on which members of the Syrian opposition - both armed and political-may participate. But the framework itself does not list mutually acceptable opposition groups precisely because the parties do not agree on such a list. The group's fortunate enough (or neutral enough) to gain the approval of the U.S., Russia, and Iran will certainly exclude many of the most powerful factions on the ground.