The Donald Trump administration’s announcement that it plans to nominate veteran diplomat David Satterfield as ambassador to Turkey could shake up US policy in Syria. The post has sat vacant for more than a year as relations between Washington and Ankara have deteriorated over the Pentagon’s backing of a Syrian Kurdish group in the fight against the Islamic State.

Why it matters: Satterfield’s confirmation could pit two influential diplomats against each other as the Trump administration tries to hammer out a deal — with or without Turkey — to establish a safe zone to protect the US-backed Syrian Democratic Forces in Syria’s northeast. That effort is led by Jim Jeffrey, who serves as both US representative on Syria engagement and envoy to the global coalition against the Islamic State. Jeffrey, who served as ambassador to Turkey from 2008 to 2010, is seeking support from US allies to provide troops for that effort. At the Munich Security Conference this weekend, Acting Defense Secretary Patrick Shanahan urged US allies to stay in the fight in Syria even as the United States targets an April withdrawal.

Big player: But Satterfield, who would arrive in Ankara fresh off his role as acting head of the State Department’s Near Eastern Affairs bureau, is likely to have his own strong ideas about the talks and could clash with the existing team at the State Department, especially on Iran. Al-Monitor reported this past summer that Satterfield’s bureau supported a gradual withdrawal from a cease-fire deal with Russia near Israel’s border that allowed President Bashar al-Assad’s troops to retake rebel-held areas, potentially giving Iranian militant groups free rein over the area, while Jeffrey has targeted the removal of Iranian proxies as a key US objective in Syria. On the ground, the Kurdish-led US allies are telling outgoing US Central Command chief Joseph Votel that they want 1,500 American troops to stay in Syria to help finish the job against the Islamic State.

UN vacancy: The United States may have a pick to lead diplomatic efforts with Turkey, but it is still missing a permanent envoy to the United Nations following Nikki Haley’s departure at the end of the year, even though the administration’s stated Syria policy ends with UN-backed talks. Former State Department spokeswoman Heather Nauert dropped out of contention on Saturday. Progress on the UN-led Geneva talks slowed in December when Assad failed to submit candidates to write Syria’s post-war constitution.