The first Western leader to do so, US President Donald Trump called Turkey’s President Recep Tayyip Erdogan to congratulate him on the outcome of the Turkish referendum on April 16. This has already had unfortunate consequences. Like a similar phone call with president Barack Obama in July 2015, which allowed coalition forces to use the Incirlik airbase in southern Turkey for sorties against Islamic State (ISIS), Erdogan has understood this has given him a free hand to deal not only with Kurdish insurgents in Turkey but now also their counterparts in northern Syria.Similarly, when vice president Joe Biden arrived in Ankara last August to assure Erdogan of US support after the failed coup, Turkey took advantage of the situation to launch Operation Euphrates Shield, an incursion into Syria ostensibly aimed at ISIS but essentially to prevent the Kurdish PYD (Democratic Union Party) and its military wing, the YPG (People’s Protection Units), from establishing a contiguous Kurdish zone south of Turkey’s border.The referendum result, a narrow win by 51.4%, is a dubious affair which reinforces Erdogan’s powers as president and removes the checks and balances considered necessary in a democratic society.Since the failed coup last July, President Erdogan has been able to rule by decree, as the state of emergency has been extended for a third time until July this year. Apart from the massive roundup of alleged plotters (to date over 135,000 have been dismissed, over 113,000 have been detained and 47,000 jailed), access to over 114,000 websites, including Wikipedia, has been blocked as they are considered sources of subversive propaganda.In 2005 Erdogan, then prime minister, was the first Turkish leader openly to acknowledge that Turkey had a Kurdish problem, and secret talks were held in Oslo between the outlawed PKK (Kurdistan Workers’ Party) and the head of MIT, Turkey’s national intelligence organization. In 2013 the PKK’s jailed leader, Abdullah Ocalan, called for a cease-fire with Turkey, which held for the next two years. At the end of February 2015 a consensus was reached between Turkey’s AKP (Justice and Development Party) government and the Kurdish-based HDP (Peoples’ Democratic Party) with a 10-point plan which would lead to a resolution of the conflict.However, the June elections in 2015, when the HDP came into Parliament with 80 out of 550 seats and the AKP lost its overall majority, upset the applecart. Erdogan, who had been elected president the year before, saw his plans for a super-presidency recede, and consequently turned his back on the peace process. The reignition of the war with the PKK has led to the devastation of several towns in the Kurdish southeast, half a million displaced persons and the resumption of terrorist bombings in Turkish cities. To this must be added the conflict with ISIS and the purge of the Gulen movement, a former ally, which has been held responsible for the coup.After initial successes against ISIS in Jarablus and Dabiq and the hard-won capture of al-Bab, Turkey’s Operation Euphrates Shield has ground to a halt, and Turkish forces have failed to advance on the town of Manbij, west of the Euphrates, held by the mainly Kurdish Syrian Democratic Forces (SDF). According to one analysis, it would take Turkey a further 12 months to cover the 180 km. from al-Bab to ISIS’s capital at Raqqa. Provided, of course, it was allowed to by the Russian-backed Syrian regime.US-backed Kurdish forces have taken the Syrian border town of Tal Abyad, 80 km. north of Raqqa, and have also taken most of Tabqa, a town strategically placed 55 km. southwest of Raqqa, as a prelude to the final assault.US support for the Syrian Kurds, which includes US ground forces, has put Erdogan’s nose out of joint. On April 25 he ordered a number of air strikes against Kurdish militia both on Mount Sinjar in Iraq and Mount Karachok in northeastern Syria, killing 70 and narrowly avoiding US forces. The US State Department declared it was “deeply concerned” and US forces have conducted joint patrols with the SDF along the Syria-Turkey border to prevent further air strikes. Furthermore, President Trump has approved a plan to directly arm Kurdish forces in Syria.When Erdogan arrives in Washington on May 16, Trump will also be faced by the thorny question of Turkey’s demand for the extradition of the leader of the Gulen movement, Fethullah Gulen, a Turkish imam resident in Pennsylvania. In addition, Erdogan has a personal interest in charges being dropped against Reza Zarrab, an Iranian-Turkish businessman, who has bee indicted for conspiring to evade sanctions against Iran.Given the contentious nature of the issues at stake, perhaps common ground can be found in the agreement on safe zones in Syria between Russian President Vladimir Putin and Erdogan, which Putin has already broached to Trump.The author is a regular commentator on Turkish affairs in the Danish and international press.