After pausing operations last month because of Turkish shelling, the US-backed Syrian Democratic Forces (SDF) are resuming the fight against the Islamic State (IS) in eastern Syria.

Why it matters: To put it simply, if there’s no SDF, there’s no anti-IS campaign. The Syrian Kurds who make up most of the SDF have served as the backbone of the Donald Trump administration’s military push in Syria since early last year.

The long-simmering feud between the Turks and the Syrian Kurds has derailed US plans for a rapid defeat of IS in eastern Syria. The Pentagon announced the beginning of the last phase of Operation Roundup to clear out Syria’s last IS safe havens two months ago. All the while, Syrian Kurds have been in talks with Bashar al-Assad’s regime in Damascus to carve out a decentralized enclave after the civil war comes to an end.

Strategic split: Meanwhile, US strategy appears to have also split. President Trump’s March promise to bring home 2,200 US troops “very soon” has faded over the objections of the State Department, the Pentagon and influential US national security adviser John Bolton, who has said he hopes to rid the war-torn country of Iranian proxy forces before the United States leaves.