Convince Putin Assad does not deserve Russia's support to reconquer eastern Syria

American Strike on Air Base in Syria Strains Relationship With Russia requires a finesse on the part of Secretary of State Tillerson with his upcoming visit to Russia where he can salvage relations by soothing Putin with something that makes him look good, in a manner similar to his forcing Assad to give up chemical warfare at the time of Obama's line in the sand. Its never talked about but Putin supports Assad because the only Russian naval base in the Mediterranean is located in his Alawite west coast of Syria. Putin will not be a part of making Assad depart Syria and leave this base to an uncertain future, but they could be persuaded to let Syria partition to leave Assad in charge of just this west coast enclave. Neither Iran nor Russian respect Assad's capability to unite and control all of Syria. Its telling that Assad's forces felt compelled to use chemical weapons to try an consolidate nearby Kan Sheikhoun into the Alawite fold that a vision of united Syria looks unlikely for the eastern regions, even to Iran and Russia. With this reality Tillerson should hash out a deal where Putin defends Assad's Alawite west coast enclave but helps him make the assessment that Assad stepped over the line and doesn't deserve Russia's blood and treasure to reconquer eastern Syria.