U.S. Vice President Joe Biden visited Turkey this weekend, just a fortnight after U.S. Chairman of the Joint Chiefs of Staff Gen. Joseph Francis Dunford met top Turkish officials. We are expecting Secretary of Defense Ash Carter to arrive soon.It is no surprise that such senior U.S. officials are visiting Turkey, especially at a time when the two countries are in desperate need of improving strategic cooperation concerning Iraq, Syria and DAESH.The two countries, which have a range of issues endangering their mutual interests and have made significant progress against combatting terrorism, must succeed in formulating a joint plan to counter threats emanating from the region, caused by the conflicts that have been spreading for the past two years. They need to lay down ground rules for joint measures, which are aimed at minimizing risks to their national security.However, the recent picture that emerged during Biden's visit can hardly be described as depicting a sound partnership. As the U.S. retreats from the region, the space left behind is filled by America's traditional adversaries, Russia and Iran, placing Turkey, which the U.S. describes as a strategic partner, between a rock and a hard place. Russia and Iran's ability to better project their influence throughout the region is the direct result of U.S. policies, another consequence of which has been the deterioration of Turkey's power to stabilize its neighbors to the south.As can be seen from countless examples in the past several decades, Turkey has been an honest and supportive partner for the U.S. Support for Ankara's initiatives to address the chaos in the region should be the least Turkey can expect from Washington.U.S. finally recognizing the immense and critical help which Turkey can provide for the freeing of Mosul from DAESH's grip was one encouraging development to emerge during Biden's trip.However, it is both disappointing and disturbing to see that the U.S. continues to regard the Democratic Union Party (PYD), and its military wing the People's Protection Units (YPG), as friendly. Biden, during his trip, reaffirmed that the U.S. identified the PKK as a terrorist group, but tacitly said the YPG wasn't considered so. American officials continue to ignore the direct link between the two groups to the detriment of a country they often call a close ally. Biden should have known better.While the U.S. claims there are certain categorical differences between the YPG and the PKK, evidence from the scene fails to corroborate it. The two groups are active on opposite sides of the border, one based in Northern Iraq and the other in northern Syria, but there is a direct flow of arms and militants between the two. The two are ideologically united and share the same leadership structure. The two as a whole pose a serious and unacceptable threat to Turkey. The arming of the YPG, and the fact that there is a weapons flow between the two sides, will eventually force the Turkish state to conduct cross-border operations into northern Syria, similar to the ones it is forced to launch from time to time in northern Iraq.The YPG is a militant group that has risen out of the chaos of Syria, with a supposed focus on fighting DAESH, but is actually a terrorist group which has adopted the ideology and policy aims of the PKK. Moreover, it is purposefully following a "Kurdification" campaign in regions under its control, removing groups and ethnic groups it deems as rivals. Local Arabs and Turkmens liken the YPG to DAESH due to its ideological indoctrination and war crimes, which are well documented by Amnesty International.The most sensible solution to the current quagmire is for the YPG and PKK to take a step back. The PKK needs to withdraw its forces from Turkey while the YPG abides by the warnings issued by Turkey, which has repeatedly advised the group against crossing the Euphrates toward the west.When it comes to Syrian peace talks, Turkey does not see the PYD as on the side of the Syrian opposition. It would be more appropriate for such a group, which has fought against opposition groups rather than the Assad regime, to sit on the opposite side of the table.That the U.S. and Turkey, with a decades-long alliance behind them, are now following alternative trajectories when it comes to terrorism, will harm the sense of trust. In light of the U.S.'s failure to take any action to support Turkey while ignoring the organic link between the PKK and the YPG, for whom weapons aid is still under consideration by the U.S., Biden's decision to call the PKK, which is already on Washington's list of terrorist groups, a terrorist group is hardly a remark that makes us feel grateful.