It would be hard to point to any noteworthy Mideast initiative or achievement by ousted U.S. Secretary of State Rex Tillerson. The Kurds surely won’t have fond memories of the agreements he recently reached with Turkey, which were trumpeted by the Turkish media on Tuesday.

To really understand the Middle East - subscribe to Haaretz

According to Turkish Foreign Minister Mevlut Cavusoglu, the U.S. and Turkey agreed that they will jointly supervise security in the Syrian city of Manbij, and that the Kurdish troops which captured the city in 2016 will relocate to the eastern side of the Euphrates River. Tillerson negotiated this agreement with his Turkish colleagues last month.

Admittedly, the Kurds deny that any such agreement was reached, and the U.S. Administration also hasn’t officially announced it. But there’s no reason to doubt Cavusoglu’s statement.

This is a dramatic agreement, because until a week ago, Ankara and Washington were still trading diplomatic barbs. Turkish President Recep Tayyip Erdogan demanded that America keep its promise to oust the Kurds from Manbij and collect the heavy weapons it had given them. Washington countered by threatening a military response if Turkey attacked the Kurdish forces in Manbij.

The mutual threats escalated after the UN Security Council passed a resolution on a 30-day cease-fire in Syria that included Turkey’s fight against the Kurds in Afrin. Erdogan claimed the resolution excluded Afrin and accused the State Department’s spokeswoman, who suggested that he reread the resolution, of either being incapable of reading or of deliberately distorting the text.

America thus faced a difficult dilemma — whether to reconcile with Turkey at the expense of its Kurdish protégés or continue supporting the Kurds even if it led to a military clash with Turkey.

Though Turkey’s invasion of Afrin sparked condemnations from both America and Europe, Manbij was always the real test. Most of the city’s 300,000 residents are Syrian Arabs, and the Kurds say they no longer control it, having handed power to the Manbij Military Council.

Open gallery view Turkey's Foreign Minister Mevlut Cavusoglu, left, points as U.S. Secretary of State Rex Tillerson, left, looks on, prior to their meeting in Ankara, Turkey, Friday, Feb. 16, 2018 Credit: STF/AP

But in fact, the city is secured by 5,000 troops from the Kurdish People’s Protection Units (YPG) who have merely changed their uniforms. Ankara sees them as terrorists who cooperate with the PKK, or Kurdistan Workers’ Party, which the Turks have fought for decades inside Turkey.

Since its liberation from the Islamic State in 2016, Manbij has flourished. It has largely replaced Aleppo as a major commercial center. Its supermarkets are full, its health and education systems work and the peace is kept. It is also a transit city for other Syrians seeking refuge in Syria’s Kurdish zones.

Aside from the Kurds who control the Manbij military, American soldiers and trainers are also present in the city. America has said its troops will remain in Syria until a suitable diplomatic solution is found. It justifies its continued presence with the need to finish the mop-up of Islamic State forces — even though it already announced that this war, in which it relied on the Kurds as its most effective ground forces, has been successfully concluded.

The agreement with Turkey, despite undermining America’s alliance with the Kurds, actually furthers its policy, because military cooperation with Turkey in Manbij will ensure a continued U.S. military presence in Syria and bolster Washington's argument against Russian and Syrian demands that it withdraw its troops.

Open gallery view U.S. Army Maj. Gen. Jamie Jarrard left, thanks Manbij Military Council commander Muhammed Abu Adeel during a visit to a small outpost near the town of Manbij, northern Syria, Wednesday, Feb. 7, 2018 Credit: Susannah George/AP

But the critical questions are how the Kurds will respond to this agreement, to which they weren’t a party, and whether Turkey will end its siege of Afrin in response to the Manbij deal. Turkey has already answered the latter question, saying the battle over Afrin will continue until Kurdish forces leave both the city and the province, one of the three autonomous Kurdish provinces in northern Syria.

As for possible Kurdish responses to the Manbij agreement, the Kurds don’t actually have many options. They will have to leave the city they liberated, because refusing to do so would mean fighting both Turkish and American forces, which is beyond the Kurds’ military capabilities.

For Turkey, a Kurdish withdrawal east of the Euphrates is important because it will widen the territorial buffer between the three Kurdish provinces. That will make it hard for the Kurds to achieve the territorial contiguity Turkey so fears.

The Kurds are voicing disappointment at America’s “betrayal,” but they probably weren’t surprised. The fact that America didn’t help them against the Turkish invasion of Afrin had already made it clear that they don’t top America’s priority list. That’s why they “invited” Syrian President Bashar Assad’s forces to help them fight the Turks.

Open gallery view Rex Tillerson, outgoing US Secretary of State arrives to makes a statement after his dismissal at the State Department in Washington, DC, March 13, 2018. Credit: SAUL LOEB/AFP

But the deep damage done to the relationship between the Syrian Kurds and the U.S. Administration doesn’t end with the tactical issue of who controls Manbij. It’s also liable to affect the diplomatic negotiations over Syria’s future and the character of Syria after its civil war finally ends.