PRINCETON –Türkan Saylan was a trailblazing physician, one of Turkey’s first female dermatologists and a leading campaigner against leprosy. She was also a staunch secularist who established a foundation to provide scholarships to young girls so they could attend school. In 2009, police raided her house and confiscated documents in an investigation that linked her to an alleged terrorist group, called "Ergenekon,” supposedly bent on destabilizing Turkey in order to precipitate a military coup.Saylan was terminally ill with cancer at the time and died shortly thereafter. But the case against her associates continued and became part of a vast wave of trials directed against opponents of Prime Minister Recep Tayyip Erdoğan and his allies in the powerful Gülen movement, made up of the followers of the Islamic preacher Fethullah Gülen.The evidence in this case, as in so many others, consists of Microsoft Word documents found on a computer that belonged to Saylan’s foundation. When American experts recently examined the forensic image of the hard drive, they made a startling – but for Turkey all too familiar – discovery. The incriminating files had been placed on the hard drive sometime after the computer’s last use at the foundation. Because the computer had been seized by the police, the finding pointed rather directly to official malfeasance.Fabricated evidence, secret witnesses, and flights of investigative fancy are the foundation of the show trials that Turkish police and prosecutors have mounted since 2007. In the infamous Sledgehammer case, a military-coup plot was found to contain glaring anachronisms, including the use of Microsoft Office 2007 in documents supposedly last saved in 2003. (My father-in-law is among the more than 300 officers who were locked up, and my wife and I have been active in documenting the case’s fabrications.)The list of revelations and absurdities goes on and on. In one case, a document describing a plot directed against Christian minorities turned out to have been in police possession before the authorities claimed to have recovered it from a suspect. In another, police "discovered” the evidence that they were seeking, despite going to the wrong address and raiding the home of a naval officer whose name sounded similar to that of the target.Yet none of the trials has yet been derailed. Most have had the support and blessing of Erdoğan, who has exploited them to discredit the old secular guard and cement his rule. Even more important, the trials have had the strong backing of the Gülen movement.Gülen lives in self-imposed exile in Pennsylvania, where he presides over a huge informal network of schools, think tanks, businesses, and media across five continents. His devotees have established roughly 100 charter schools in the United States alone, and the movement has gained traction in Europe since the first Gülen school was founded in Stuttgart, Germany, in 1995.Back home, Gülen’s followers have created what is effectively a state within the Turkish state, gaining a strong foothold in the police force, the judiciary, and the bureaucracy. Gülenists deny that they control the Turkish police, but, as a US ambassador to Turkey put it in 2009, "we have found no one who disputes it.”The movement’s influence within the judiciary ensures that its members’ transgressions remain unchallenged. In one well-documented case, a non-commissioned officer at a military base, acting on behalf of the Gülen movement, was caught planting documents in order to embarrass military officials. The military prosecutor investigating the case soon found himself in jail on trumped-up charges, while the perpetrator was reinstated. A senior police commissioner who had been close to the movement and wrote an exposé about its activities was accused of collaborating with the far-left groups that he had spent much of his career pursuing; he, too, ended up in jail.The Gülen movement uses these trials to lock up critics and replace opponents in important state posts. The ultimate goal seems to be to reshape Turkish society in the movement’s own conservative-religious image. Gülenist media have been particularly active in this cause, spewing a continuous stream of disinformation about defendants in Gülen-mounted trials while covering up police misdeeds.But relations between Erdoğan and the Gülenists have soured. Once their common enemy, the secularists, were out of the way, Erdoğan had less need for the movement. The breaking point came in February 2012, when Gülenists tried to bring down his intelligence chief, a close confidant, reaching perilously close to Erdoğan himself. Erdoğan responded by removing many Gülenists from their positions in the police and judiciary.But Erdoğan’s ability to take on the Gülen movement is limited. Bugging devices were recently found in Erdoğan’s office, planted, his close associates said, by the police. Yet Erdoğan, known for his brash style, responded with remarkable equanimity. If he harbored any doubt that the movement sits on troves of embarrassing – and possibly far worse – intelligence, the bugging revelation must surely have removed it.The foreign media have focused mainly on Erdoğan’s behavior in recent months. But if Turkey has turned into a Kafkaesque quagmire, a republic of dirty tricks and surreal conspiracies, it is Gülenists who must shoulder much of the blame. This is worth remembering in view of the movement’s efforts to dress up its current opposition to Erdoğan in the garb of democracy and pluralism.Dani Rodrik is Professor of Social Science at the Institute for Advanced Study, Princeton, New Jersey.Copyright: Project Syndicate