An estimation about the recent Turkish invasion in North Syria
It's hard for someone to believe that the Turkish ground forces invaded North Syria to fight ISIS. It seems that the US officials decided to calm down Tayyip Erdoğan and let him play his game for a while, in order to make him forget Fethullah Gülen and the failed coup of July.
Obama doesn't want to risk further with the unpredictable Turkish leader, especially after he showed that he may turn to Putin. Obama also wants to leave without risking further mess in the Middle East chaotic puzzle. He will leave the "hot potato" to the hands of the next US presidency.
Erdoğan knows that he has limited time before Clinton or Trump in the US presidency. Therefore, he tries to take as much as he can and negotiate from a power position when the Syrian hell will end someday.
Right now, Erdoğan's main concern is to retain his agenda, thus exploit the chaos in Syria to enhance the Syrian Turkomans and fulfill his dreams for territorial and influential expansion in the wider Middle East. This explains why Turkey demanded YPG Kurdish forces to retreat back to the east of the Euphrates. Through this move, he tries to maintain an open corridor between Turkey and Syrian Turkomans, but also, to sabotage the Kurdish attempt for an autonomous entity in North Syria.
Meanwhile, it seems that everyone forgot Assad, or, at least accepted him as an intermediate necessity before the final redrawing of the Syrian map. Therefore, all the key players try to focus on their agendas.
For this reason, it is unlikely that the US will abandon Kurds and the plan for a Kurdish state because they have invested so much in this perspective all the past years. While Obama wants to leave quietly without further trouble, it is almost certain that the next US president will not abandon these plans so easily, just for the sake of Erdoğan.