Managing alliances in Syria has always been a struggle for the United States, as underscored by how often two US-armed allies end up directly fighting one another.
Several people in Germany were left injured after police used pepper spray against some demonstrators opposed to Turkey's ongoing military operation Olive Branch against the Kurdish People's Protection Units (YPG) in Syria's Afrin region. Is this friendship? Is this North Atlantic Treaty Organisation unity?
Under NATO charter, an attack on one of the alliance's members is an attack on them all. NATO, Turkey is not a NATO country? The Turkish government views the YPG as a terror organization and the Syrian branch of the outlawed Kurdistan Workers' Party (PKK) militant group.
The military intervention came after the USA said it would set up a 30,000-strong militant border force at Turkish doorstep.
Pro-Kurdish demonstrators staged protests against Turkey's military offensive in northern Syria on Sunday scuffling with Turks and German police at Duesseldorf airport, while in Britain they temporarily closed two train stations, authorities said. "Turkey will fight terrorists anywhere they operate", Erdogan said, once again promising new military operations in Syria, including in the areas held by the US-backed Kurdish-led militias.
Overt talk of trying to rein them in is likely to add to the sense among many YPG leaders that the U.S. is a fair-weather fried that can't be counted on when the chips are down.