Turkish Prime Minister Binali Yildirim did not mince his words when he accused the self-exiled Islamic cleric Fethullah Gulen of being behind the coup d'etat that attempted to overthrow President Recep Tayyip Erdogan and his government on July 15.

In a thinly veiled reference to the preacher's current home in the US – in a mansion-like retreat in Saylorsburg, Pennsylvania – Yildirim accused Gulen of being the "leader of a terrorist organisation" and said that "any country that stands by him is at war with Turkey".

Gulen, who has a big following in Turkey and around the Muslim world through his Hizmet movement, is a former ally of Erdogan's, but had a falling out with the Turkish head of state in late 2013 and has since become the target of a massive witch-hunt.

The man whose name has become synonymous with treason in Turkey – and who could now become the cause of a diplomatic row between the two Nato allies – denies accusations that he was the mastermind behind the attempted government overthrow.

"I categorically deny accusations of a role in the attempted coup," he said in a statement on July 15. "As someone who has suffered under multiple military coups, it is especially insulting to be accused of having any link to such an attempt."

He even told the Financial Times that the coup may have been staged by Erdogan himself.

Relations between Washington and Ankara were already tense over US criticism of the Turkish government's crackdown on democratic freedoms, the case of Turkish-Iranian businessman Reza Zarrab who is being prosecuted in New York, the US' support of Syrian Kurds, and Turkey's standoff with its own Kurds in the southeast. If Gulen becomes an additional pillar of discord, relations could deteriorate fast, calling into question the US' use of Turkey's military bases in the short term or even Ankara's standing in Nato altogether.

While in the past Ankara has merely urged Gulen to return home and warned Washington about the threat that he poses, the current mood in the Turkish capital is that his extradition is a diplomatic obligation if the US wants to maintain good bilateral relations with Turkey. 

Erdogan demanded the US extradite Gulen on July 16. “This country suffered a lot in the hands of the Gulen movement,” he told a news conference. “They undermined Turkey’s reputation in Europe and the US. I call on the US and President Barack Obama... Either arrest Fethullah Gulen or return him to Turkey.”

Ankara believes the US needs Turkey’s close cooperation in this explosive geography, with Islamic State being the foremost problem to be tackled. Following the coup Ankara closed the Incirlik air base, which is used for bombing Islamic State positions. The government said it was a precaution – the base had been used by the coup plotters – but it may also think it has a bargaining chip.

Caught off-guard during a visit to Luxembourg on July 16, US Secretary of State John Kerry said that Washington had not received a request to extradite the Muslim cleric, and that Ankara would have to present evidence of his wrongdoing for an extradition to take place.

“We invite the government of Turkey to present us with any legitimate evidence that withstands scrutiny and the United States will accept that and look at it and make judgments appropriately,” the US Secretary of State said.

But the excuse will not work for much longer, for the wheels had been put in motion to officially ask for Gulen's extradition even before the coup d'etat.

At the time of writing, there was no proof whatsoever that Gulen was the mastermind behind the coup, although AKP supporters widely suspect Gulenists in the military of staging the coup in order to prevent their own removal in a planned purge.

Indicted by an Istanbul court in October for attempting to overthrow the government, Gulen's quiet life in Pennsylvania now hangs by a thread.

The US is now caught between a rock and a hard place. If it obliges Turkey in order to maintain good relations with its military ally, and if Ankara reintroduces the death penalty for treason as Yildirim also threatened on July 16, Gulen's life could be at risk.

But if it denies Turkey’s request for the extradition of Gulen, it will look like it backed the coup in the eyes of many AKP supporters and it risks alienating its long-time strategic ally. AKP supporters are already asking: “Does Gulen have powerful friends in Washington? Is he an ‘important asset’ for the US?”

Turkish Minister of Labour Suleyman Soylu seems to have his own answers to these questions. Soylu bluntly said on July 16 that the US was behind the coup attempt. The proof: US’ harbouring of Gulen.

A cult-like movement

Born to an imam father and a teacher mother in a village in eastern Turkey, the 75-year-old Gulen developed his philosophy and preaching style during a time when Turkey was as besieged as it is at the moment, with frequent clashes between secularists and rightwing nationalists, which led to a military coup in 1960.

A firm believer in education as a means to restore the social morals that he believed were failing, Gulen began teaching a version of Islam that supported democracy, science and interfaith dialogue – particularly among “People of the Book”, as Christians, Jews and Muslims are defined in the Qu'ran – in the northern town of Edirne in 1960.

According to Professor Helen Ebaugh from the University of Houston, who wrote a biography about the preacher: "When Fethullah Gulen began preaching, his message was that we don't need more madrassas, we need schools to teach science and maths and secular subjects. And his contingent was that one can be modern, and one can be scientific, and still be a good Muslim."

By the 1970s, having moved to Izmir and speaking to a growing number of supporters in coffeehouses, he was arrested for the first time during a military coup in 1973 and spent six months behind bars before being released on the condition of refraining from giving any more public lectures.

After the first Gulen-inspired school was founded in Izmir in the 1980s, the movement spread to more than 160 countries over the next three decades through some 1,600 schools. Schools have mushroomed from Texas to Japan, and from Mexico to Somalia, although many of them did not even teach religion, let alone Islam, but were focused on science and on enabling students to pass standardised exams and be admitted into higher education.

Gulen's influence over his followers stemmed from the appeal of his message of charity, education, humanism, and interfaith dialogue; he met with Pope John Paul II in 1998 and has advocated for religious minorities.

While he has refrained from amassing wealth himself, his movement has become unbelievably rich, not least because he urges followers to donate 10% of their income to the causes of furthering education, civil society and volunteer organisations, media and other fields. Alumni of Gulenist schools keep in touch through tightly knit alumni organisations, and help younger generations in climbing their way to the top in business, political and academic careers.

In 1986 he was detained for a second time after spending six years on the run from the military junta at the time, which saw itself as a guarantor of secularism in Turkey. The junta accused him of trying to overturn the government in order to establish Islamic law. Gulen only walked away free after the then-prime minister, Turgut Ozal, became his "guarantor".

After travelling to the US in 1999 to seek medical treatment for a host of illnesses that included diabetes and cardiovascular problems, the preacher continued to keep in touch with Hizmet advocates through weekly sermons and statements published on his personal websites, as well as through the business empire around him that comprises media outlets such as TV channels Samanyolu and Mehtap TV and publications such as Today's Zaman.

His decision to remain in the US following his initial medical visit, however, was prompted by the leak of a tape of one of his sermons in which he advised his followers to "move in the arteries of the system without anyone noticing your existence until you reach all the power centres… You must wait for the time when you are complete and conditions are ripe, until we can shoulder the entire world and carry it...You must wait until such time as you have gotten all the state power, until you have brought to your side all the power of the constitutional institutions in Turkey... Until that time, any step taken would be too early—like breaking an egg without waiting the full 40 days for it to hatch. It would be like killing the chick inside.”

The tape brought about the first accusations of attempts to infiltrate state institutions in Turkey, and the cleric chose to remain in Pennsylvania instead of running the risk of being arrested if he returned home.

A growing threat

Supporters describe Gulen, who was included in Time magazine's list of 100 most influential people in the world in 2013, as a kind, enlightened spiritual leader who has forcefully condemned Islamic terrorism and promoted humanist values such as education and charity.

But his growing following has not been without its critics, particularly from the administration of Erdogan and of the ruling Justice and Development Party (AKP) in recent years, which have accused Hizmet of infiltrating state institutions.

Hizmet and Erdogan had lukewarm relations in the beginning of the latter's rule as prime minister in 2003. Brought together ironically by the threat of a military overthrow of the AKP government, relations between the AKP and Hizmet have always been strained by an undercurrent of distrust; it emerged in later revelations there was widespread government profiling of Gulenists during those early years.

The launch of an investigation in 2007 against Ergenekon, an alleged clandestine secularist group in Turkey with ties to the military and security forces, cemented the uneasy partnership. Prompted by the discovery of alleged evidence on plans to overthrow the government, Ergenekon evolved into a government-led purge of some 500 police officers, judges, military officials and journalists deemed to be enemies of the state. Gulenist prosecutors and security officers were reportedly instrumental in the arrests, and they co-operated with the AKP to eliminate secular, anti-government elements from the security forces.

In a style that bares an uncanny resemblance to the current anti-Gulenist drive, the government dubbed Ergenekon a "terrorist organisation" and blamed it for most acts of political violence perpetrated in Turkey over the last three decades.

Later when it fell out with the US-based cleric, the AKP government claimed that it was “deceived” by Gulenists and all the evidence used against soldiers and other people convicted in the Ergenekon case was fabricated. It released all of them from prison and ironically chucked the journalist Mehmet Baransu, who had “revealed” the Ergenekon coup plans, into jail.

Following a high-level corruption scandal in December 2013 that implicated Erdogan and his son Bilal, among others, Ankara launched an outright war against the Gulen movement, which it accused of trying to overthrow the government by publishing incriminatory recordings on YouTube that revealed government corruption.

Erdogan himself has been at the forefront of the anti-Gulen frenzy, accusing the preacher of treason by creating a "fifth column" to discredit and ultimately overthrow his government, revoking his Turkish passport, accusing his movement of being a terrorist organization, launching wide-ranging purges of the judiciary, military and police forces in which thousands of officials were replaced, and through raids at or takeovers of business conglomerates and associations linked to Gulen, such as Koza-Ipek, Kaynak Holding, Boydak Holding and Bank Asya.

Opinions are divided over just how great the extent of the Gulenists' control over state institutions was. Ebaugh, for instance, believes that their representation in the bureaucracy was not greater than the ratio of Gulenists in the general Turkish population, which is believed to be around 10%. AKP supporters, on the other hand, counter that Hizmet members controlled more than a fifth of the government bureaucracy.

"The way the Gulenist movement works is that, starting some 30 years ago, they would pick bright middle school and high school students [from the thousands of schools they run worldwide]. They would give these students the answers to exams so that they got high scores and would feed them into the military and police academies or law schools. For such students, their first loyalty is to the Gulen movement, instead of the institutions the come to work for, the country or the people. The movement work like a cult," Zeynep Jane Louise Kandur, a board member in AKP's Istanbul branch, told bne IntelliNews in an interview on July 16.

"Gulen wants control of the government not necessarily to further his ideology or business interests, but for the sake of power. AKP and the Gulen movement worked together for a [decade] before 2013, but the movement became undemocratic and started to have ever higher demands to control various institutions, and that is where the line was drawn and the conflict between the AKP and Gulenists started," she elaborated.

The government clearly sees the coup as an opportunity to finally cut out any remaining Gulenist influence from the Turkish state. Following the coup, it has immediately dismissed some 2,745 judges, including five Supreme Court judges, in addition to arresting over 2,000 military personnel. All are accused of being associated with Gulen.

Yet the jubilation with which Erdogan and his administration responded to Gulen's alleged implication in the coup raises questions about the extent to which the AKP is fabricating or exaggerating the accusations in order to serve its own political goals of tightening its grip on power. By blindly pursuing his bogeyman, Erdogan risks damaging Turkey’s vital relationship with the US, enfeebling state institutions, and wrecking Turkish democracy and rule of law.