The power alignments between the nations of the Middle East are like dominoes. The master key to thwarting the revolutionary ambitions of aggressor states such as dominant Iran is the status of European Constantinople and the Balkans.
Historically, Russia has an interest in the future of Constantinople and likely could be induced to withdraw its support for the Assad regime in exchange for an ice-free seaport closer to its goals in Europe.
Unlike Turkey, Russia is European. The settlement in identity of Turkey as European or Asian will facilitate the resolution of many other questions related to the Middle East.
When the Assad regime ends, the aspirations of Iran related to the demise of Israel as well as an expansive entry into Europe will also end.
Constantinople should be internationalized under the United Nations or a special regime. The remaining Turkish territory west of the Dardanelles and all waterways connecting the Black Sea and the Mediterranean Sea ought to be apportioned to surrounding nations in accordance with the historic character or the peoples and terrain fitting the best prospects for peace.