Sipping black tea in a cafe overlooking central Ankara, Ahmet Faruk Unsal reflects on his time with Turkey's ruling Justice and Development Party (AKP) as supporters prepare to mark the 16th anniversary of the party's founding.

Unsal served as AKP deputy for the southeastern province of Adiyaman from 2002 to 2007, a period he describes as the party's "Golden Age."

"[At that time,] they had good relations with Europe and were seen as a democratic model for the Muslim world," he told DW. "Then they began to erase the progress they had made."

Under the leadership of its most charismatic member, current President Tayyip Recep Erdoğan, the party improved access to social services for the nation's poorest, undertook infrastructure mega-projects and stabilized the economy, making Turkey attractive to foreign investment.

Read more: Erdogan returns as ruling AKP party chief after referendum win

Yet after 2007, the party passed a series of constitutional amendments that consolidated its power and began to crackdown on opponents, drawing international criticism first during the 2013 Gezi protests, and later for ongoing mass purges following last year's coup attempt.

The AKP still maintains support from about half of Turkish voters and is revered by many for having brought political representation to the nation's pious citizens, but as Erdoğan takes the stage Monday evening at an anniversary rally in a suburb of Ankara, his party's legacy is increasingly deemed as authoritarian by opponents and Western observers.

The country remains under a state of emergency as efforts to persecute suspected coup plotters have spread to critical institutions, NGOs and media outlets. In March, Unsal was relieved of his position as chairman of Mazlumder, Turkey's main human rights organization, along with more than 3,000 colleagues.

"The public initially had sympathy for Erdoğan and the AKP founders because they were oppressed by the state for the religious views … now they have become the oppressors," Unsal said. "Under normal democratic conditions, [they] would lose."

Predestined to be authoritarian?

Recent developments have sparked a debate among Turkish and international observers over whether the AKP was predestined to be authoritarian or has arrived at its current position due to circumstances specific to Turkey's political habitat. Some argue the country's founder, Mustafa Kemal Atatürk, built a highly centralized state based on singular expressions of identity and nationalism in a multicultural country that the AKP has since adapted and reshaped.

Whereas Atatürk's 'Kemalism' pushed secularism as a core characteristic of Turkish nationalism, Erdoğan increasingly restored the role of Islam in Turkish identity. He was able to do so, according to Howard Eissenstat, an Associate Professor at St. Lawrence University and nonresident senior fellow at the Project on Middle East Democracy, through existing forms of clientelism in state bureaucracy and high parliamentary thresholds barring opposition parties from entering the political arena.

Read more: Erdogan takes on Ataturk

In turn, AKP was able to monopolize the center-right, which Eissenstat defines as the "sweet spot of Turkish politics." Though Eissenstat said he believed AKP's initial reforms were wide spanning and genuine as the party reached out to non-Muslims, Kurdish and Armenian communities in Turkey, efforts to foster a more inclusive state have largely receded.

"What's striking about today's abuses isn't that they're innovative in the broad sweep of Turkish history, most would have quite normal in the 1990s, but rather that they represent a very clear rolling back of reforms that the AKP itself had implemented," Eissenstat told DW in a phone interview.

Turkey's international standing has been marred by the deterioration of the Kurdish peace process in 2015 along with wide spanning post-coup crackdowns that have led to the dismissal of more than 100,000 workers while more than 50,000 suspected coup plotters languish in jail. Recent spats with European nations have also brought Turkey's EU accession process to a halt, but Eissenstat said EU membership is not high priority for most AKP supporters.

"It wasn't a question for them if they were part of the European Union or not. The EU was a measure of whether Turkey was a first tier power," Eissenstat said. "That can happen outside of the European Union or inside the European Union."

Upcoming elections, ongoing resistance

Looking ahead, Turkish voters face municipal elections in 2018 and presidential elections in 2019. The AKP continues to enjoy unparalleled dominance in Turkish politics due to the strength of the economy and the weakness of opposition parties. While unforeseen circumstances could change AKP's standing among its voter base, Eissenstat said discrepancies in the April referendum have cast doubts on the legitimacy of polling results.

Read more: Opinion: Erdogan prepares for 2019

"Even if [Erdoğan] were to suffer a dramatic loss of popularity, it's hard to imagine him allowing an election to push him out of office," Eissenstat said.

Back at the cafe in Ankara, Ahmet Faruk Unsal mulls over the AKP's legacy and says he can no longer view the party in a positive light. He says he was always critical of AKP tactics, even as a deputy, and that he remains optimistic in the face of increasing authoritarianism.

"People looking from outside of Turkey should take into consideration that we don't have freedom of the press, that members of parliament are put in jail with not just journalists, not just [suspected coup plotters], but with all different opposition groups and still we are resisting [Erdoğan], still we have courage," Unsal said.