As the delivery date of the Russian S-400 air defense system to Turkey — scheduled for July — closes in, the US is making efforts not to leave any stone unturned with a view to accommodating at least one of Ankara’s expectations: The setting up of a safe zone in Syria in exchange for Turkey’s stepping back from the S-400 issue. The two countries’ perceptions on the safe zone issue are still far apart, but compromise solutions are being eagerly sought by both sides. Turkey’s initial position on this issue was to establish a security belt 30 kilometers deep into northeastern Syria, to be protected exclusively by the Turkish army. The US attitude on the same subject was expressed by State Department spokesman Robert Palladino, who warned of “the potentially devastating consequences of unilateral Turkish action in the region.” Washington has supplied the Syrian Democratic Forces (SDF), whose backbone is composed of Kurds, with tens of thousands of truckloads of weapons, equipment and ammunitions, claiming that this was to help the Kurds fight Daesh. This may be true to a large extent, but Washington’s more important aim was to aid the emergence of a Kurdish entity in the region to be used as leverage against the Assad regime during Syria’s democratization process. A Kurdish autonomous or independent state in the region would also boost the security of US ally Israel. This US policy has fueled distrust in Ankara. In an effort to eliminate it, Washington made a move to soften its attitude on the safe zone issue. It now seems to be — though reluctantly— in favor of “a limited number” of Turkish forces being allowed to enter Syrian territory. Such a move is preferable for the US over an uncontrolled incursion launched unilaterally by Turkey. The Kurds announced that Washington raised this idea in negotiations with them. The Kurds are furiously opposed to any Turkish military presence anywhere in Syria, particularly in the northeast. If the US succeeds in persuading the Kurds, this may be the beginning of a breakthrough. But everything in Turkish-US relations is linked to other issues both within the bilateral and broader contexts. Russia is watching to see if the Kurds feel betrayed by Washington, so that it could step in and try to encourage them to more closely cooperate with the Damascus regime.If the US succeeds in persuading the Kurds to let a “limited number” of Turkish soldiers into Syria, Washington would expect concessions from Turkey in exchange for its efforts. Since the most urgent issue is the deployment of the S-400 system in Turkey, the US will probably expect Ankara to step back from the purchase of this Russia-made air defense system. But Ankara does not have much room for maneuver. It has informed Washington several times that the S-400 is a done deal. It has repeatedly confirmed this to Russia as well. Stepping back from it now would seriously erode Turkey’s credibility. For the moment, Russia is absent in this scenario, but Moscow has made it crystal clear on several occasions that the logical course of action after the withdrawal of US forces from the region would be to fill the void with Syrian government forces. Since Russia is also a strong supporter of the Kurdish cause, Washington and Moscow may work out a modus vivendi. This will, of course, be a big disappointment to Turkey. Another relevant actor not mentioned so far is Iran. Tehran is uneasy regarding the American presence and that of its Kurdish proxies. Therefore, it may mobilize its own means to undo any scenario designed by Washington. To top this intricate game plan, there are unconfirmed rumors in the Turkish media saying that there has been indirect contact between Turkey and the SDF. If this is true, they may be through the American channels because Washington is close to both Turkey and the Syrian Kurds. The irony here is that both Ankara and Damascus have converging interests in containing the Kurdish aspirations in the north of Syria but, probably because of the too-tough position adopted so far by Turkey toward Bashar Assad, it has difficulties in stepping back. Iranian Foreign Minister Mohammed Javad Zarif visited Ankara after leaving Damascus two weeks ago. He said he had a long conversation with Assad and that he would report its content to Turkish President Recep Tayyip Erdogan. Nothing has leaked from this meeting, but one can assume that Zarif must have conveyed an accurate picture of Assad’s thinking. Whether this made an effect on the Turkish president is not easy to guess.