Recent months have witnessed increasing deterioration of the US-Turkey relations. Both sides have traded barbs and accusations and imposed sanctions against each other. Earlier this month, Washington slapped sanctions against Turkey’s justice and interior ministries, prompting Ankara to reciprocate in kind. The Trump administration announced that it would double its tariffs on Turkish steel and aluminum, causing the Lira to nosedive abruptly. President Erdogan urged the Turkish people to boycott the US-made electronic devices, instigating some people to break their iPhones. The apparent cause behind the antagonism seems to be the continued detainment of American Pastor Andrew Brunson (now under house arrest) by Turkey. The latter has accused him of espionage, working in cahoots with terrorist organizations and being complicit in the bungled military putsch of 2016. In his June 26 tweet, President Trump said, “The United States will impose large sanctions on Turkey for the long-time detainment of Pastor Andrew Brunson, a great Christian, family man and wonderful human being.” The detainment of Andrew Brunson might be a source of concern for the Trump administration, especially for vice-President Mike Pence, a Christian supremacist. More so given that congressional elections are in the offing in the coming November and the Republican Party would play to the gallery to appease its core constituency and garner votes. But the diplomatic rift between the two strongest NATO members cannot possibly be attributed to a single act of incarcerating of an evangelical missionary. In recent times, Turkey and the US have pursued divergent geo-political interests, which, at one time, even brought them on the verge of direct military clashes in Manjib in northern Syria. The spectre of military hostilities was only averted when the US agreed in June 2018 to make the Syrian Democratic Forces (SDF) vacate the town and allow Turkish military forces to patrol the town jointly with American Special Forces. The US has been providing weapons, training and air-cover to Syrian Democratic Forces, pre-dominated to the Kurdish People’s Protection Units (YPG), since mid-2014, when it began its military campaign against the Islamic State (IS). Avowedly secular, battle-field tested and in need of a foreign patrol, the U.S found in Kurdish militia a ready partner that would compensate the lack of American ground troops in Syria to fight IS. The Trump administration’s silence over the detainment of other American citizens, like SerkanGolge, the NASA scientist, lends credence to the view that there is more to the US-Turkish relations than the continued incarceration of Pastor Andrew Brunson But Turkey considers People’s Protection Units a sister organization of Kurdish Workers Party (PKK), declared a terrorist entity not only by Turkey but also by the U.S and EU, which has waged an intermittent insurgency since 1980s in the southeastern part of Turkey for greater autonomy for the Kurdish people. Turkey has feared that an autonomous Kurdish region in northern Syria in control of a militia that has battle-field experience, a huge cache of modern American-supplied arms and organizational linkages with PKK would negatively affect Turkish national security by emboldening militant Kurds in Turkey and spread insurgency there. That came to materialise in 2015 when Turkey and the PKK ended the ceasefire and restarted the war. To protect its interests, Turkey militarily intervened in Syria by launching operation ‘Euphrates Shield’ in August 2016, lasting till March 2017. Notwithstanding Turkish claims of fighting ISIS, the primary motive of the military operation was to deny Kurdish regions geographical contiguity by halting the movement of YPG on the Euphrates River. Turkey again sent its military forces across the border in January this year to take the north-western city of Afrin from Kurds. Islamic militants marched alongside Turkish military forces in what Ankara ironically called operation ‘Olive Branch.’ Both sides have accused each other of working at cross-purposes to undermine their respective interests. America blames Turkey of weakening its campaign against IS by attacking its Kurdish allies in Syria. While Turkey resents the American decisions to support Kurdish forces and not to extradite Fetullah Gulen, the alleged hand behind the military coup of, 2016 in Turkey. Despite the incident of Turkish warplanes downing a Russian SU-24 in November 2015, Turkey and Russia have moved forward to develop strong bilateral ties over the last few years. Both states have cooperated in nuclear energy and gas projects. Turkey is part of the Russian-led Astana peace talks in Syria, an alternative platform from the UN-led Geneva process to find a ‘political settlement’ to the conundrum of Syria. Last year, Turkey agreed to buy S-400 surface-to-air defense missiles systems from Russia. In 2015, the US, Germany and the Netherlands had decided to end the deployment of Patriot missiles in southern Turkey, prompting Ankara to look for Moscow to acquire missile batteries to meet its defense needs. Of all the above factors, this has been the most important driver of mutual acrimony between Turkey and the US Officials in the Trump administration have raised concerns regarding the purchase of S-400 missiles by Turkey from Russia, citing unspecified security threats and dangers. Moreover, the US has also accused Turkey of undermining and diluting the effects of sanctions on Iran by maintaining trade ties and importing oil from it. The diplomatic rift and political antagonism between the US and Turkey is the culmination of accumulated tensions emanating from divergent geo-political interests, pushing the two strongest NATO members on the path of a possible political collision. The case of Pastor Andrew Brunson is just the tip of the iceberg, not necessarily the primary driver pushing the Turkish-U.S estrangement. Had it been so, it would not have taken the US one and a half year to wait prior to earnestly taking up the case of an evangelical missionary. He was arrested in December 2016. Moreover, the Trump administration’s silence over the detainment of other American citizens, like Serkan Golge, the NASA scientist, lends credence to this view that there is more to the US-Turkish relations than the continued incarceration of Pastor Andrew Brunson. The writer works as a researcher in the Islamabad Policy Research Institute (IPRI) Published in Daily Times, September 3rd 2018.