Unfortunately the U.S. has long resisted a diplomatic solution. In 2015 the Guardian disclosed that the U.S. turned its back on efforts by Russia to bring about a diplomatic solution as far back as 2012.
And in 2015 Philip H. Gordon, Senior Fellow for the influential U.S. 'think-tank' Council on Foreign Relations wrote "Syria: The Need for Diplomacy and De-escalation". Gordon advised that U.S. policy was not working and would never work, that a diplomatic solution was the way to peace in Syria. The U.S. policy makers were not listening and apparently continue to refuse to listen to any diplomatic solution.
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