The suicide attack that killed several US service members and civilians in Manbij today may strengthen Turkey’s hand against Syrian Kurdish groups that it sees as a threat. Ankara has been arguing the US-backed Kurds are unwilling or unable to maintain stability and security in the areas they control in Syria, and is eager to replace them with its own proxies.

Why it matters: The presence of groups affiliated with the Syrian Kurdish People’s Protection Units (YPG) in Manbij had been a major point of contention between Washington and Ankara until Trump’s decision last month to pull out US troops. Now Ankara is widely seen as waiting for US forces to leave the area before it launches a military operation to take the city.

Turkey considers the YPG a terrorist organization and a threat to its national security. It also argues that Kurdish groups are not able to defend the lands they control in Syria from the Islamic State or other terrorist groups.

Today’s rare attack may provide fresh ammunition for Ankara’s arguments against the YPG. However, the attack also further complicates that equation, as it puts the lie to the idea that the fight against IS is almost over — Trump’s rationale for pulling out in the first place.