On May 9, it became known that the administration of the US President Donald Trump has authorized the provision of heavy weapons to Syrian Kurdish militias to drive ISIS terrorists from the city of Raqqa.
As civil war raged near the capital, Kurdish-led Syrian forces far to the north pressed a separate offensive against Islamic State extremists just outside the de facto IS capital, Raqqa.
Obama's policy to support the YPG as the most effective fighting force against jihadists in Syria enraged Ankara, who regard the group as the Syrian branch of the Kurdistan Workers Party (PKK) which has waged an insurgency inside Turkey since 1984.
"Once a "model partnership", the relationship deteriorated into a dysfunctional one with unsatisfactory results for both sides", said Kemal Kirisci of the Brookings Institution and Asli Aydintasbas of the European Council on Foreign Relations in a study of Turkey-US relations. "The head of this terror organization is living in the U.S. Since we are partners as we are friends and friendly countries, you should deport him as soon as legal procedures are complete". "We were hopeful", a senior Turkish official said afterward. Therefore, the United States president's decision to supply heavy weapons to the Syrian Kurds was a cold shower for the leadership of Turkey.
During the Turkish delegation's trip to Washington, President Trump approved a plan to provide weapons to YPG militants in Northern Syria - which was not a popular decision in the Turkish capital.
Turkish Justice Minister Bekir Bozdag voiced disappointment about what Turkey sees as the US reluctance to extradite Fethullah Gulen, a Pennsylvania-based cleric accused by Erdogan of being the mastermind of last year's coup attempt. The arms provided the YPG have a very good chance of being used to support the PKK against the government of Turkey unless the United States can find a way to prevent it.
Trump, who has said that he will be "respectful" of the domestic decisions made by other governments, is unlikely to dwell on the mass arrests and restrictions on free expression since the coup attempt, about which even his own State Department has expressed concerns.
On Syria, the sticking point between Turkey and the United States is no longer whether Bashar al-Assad will keep his seat.
Turkey's military operation in northern Syria was effectively limited by both the USA and Russian Federation, and the whole affair was halted a while ago. Erdogan saw this as a refusal to cooperate against a criminal terrorist, helping to sour further the already hard relationship between his government and the Obama administration.
Erdogan, who was speaking at a news conference in the capital Ankara, also said he would pursue the issue of the extradition of the US -based cleric Fethullah Gulen to "the end".
At the end of the day, Kahl said, Trump came to the same conclusion as Obama, but only after Erdogan had won his referendum without the annoyance of an open breach with Washington.
On Wednesday, Turkish President Tayyip Erdogan called on the U.S.to reverse its decision.
"Put yourself in the shoes of the Turkish president", the official said.
Meanwhile, more than 1,200 residents and opposition fighters trapped in the Syrian capital Damascus left their neighborhoods for rebel-held Idlib province Friday as part of a deal to return the last neighborhoods of the capital to government control.
Some senior Turkish officials last week said the USA policy toward the YPG amounted to support for terrorism, putting the government on an apparent collision course with Trump ahead of Erdogan's meeting.
After some sabre rattling, the Turks made clear it would not attack USA forces present with YPG forces.
Barack Aydin of the Washington-based Kurdish Policy Research Center, said the key ought to be a broader peace process between Erdogan's government and Kurdish opponents in Turkey, which would eliminate these problems.
Turkey also retains the option of canceling an agreement that allows US and anti-Islamic State coalition warplanes to fly out of its air base at Incirlik.