Political divisions in Turkey were on full display this week, as a court sentenced hundreds of former military officers, opposition politicians, journalists and academics for plotting to overthrow Prime Minister Recep Tayyip Erdogan and his Justice and Development Party (AKP) in a conspiracy case that has gripped the nation.

The highest-profile defendant of the 275 on trial was former armed forces chief Ilker Basbug, who on Monday received a life sentence in jail, along with 17 others - including retired generals.

Judges also sentenced three serving parliamentarians from the opposition Republican People's Party (CHP) to between 12 and 35 years in prison. The court freed 21 defendants.

All have been accused of being members of a little known underground group dubbed "Ergenekon", the name of a mythical valley in Central Asia where the Turks are said to have originated.

The landmark trial started in 2008, after an anonymous tip led police to find explosives in a ramshackle house in Istanbul. That discovery led to indictments that ran for tens of thousands of pages. The trial became a sharply debated manifestation of the deepening divide between the government and its conservative, religious base on one hand, and opposition secularists on the other.

Turkey's media: Caught in the wheels of power?

The case highlighted these underlying tensions - which date back to the early years of the modern Turkish republic, founded by Mustafa Kemal Ataturk from the ruins of Ottoman Empire.

The convictions were seen as a triumph for democracy by Erdogan's supporters. They are considered a rebuke of the military's political influence, after the army staged three coups between 1960 and 1980, and hounded an Islamist-led government from office in 1997.

But many others have criticised the trial for being politicised, and some consider the convictions to have been unfair.

"We were expecting to find an independent judicial system and an unbiased one," Ersan Sen, a professor of Turkish law, told Al Jazeera. "Now, unavoidably, there is concern in society that [the] judicial system is being used as a political tool."

Emine Ulker Tarhan, a parliamentarian from the opposition CHP, echoed similar concerns. "All [the] evidence was shady; the harsh sentences are shameful," Tarhan told Al Jazeera. "All this oppression will increase the power base of the opposition."

In contrast, political commentator Oral Calislar, once a prominent leftist and 1960s revolutionary student leader, said the Ergenekon verdicts secured the functioning of democracy in Turkey. "There were already two camps, people opposing military guardianship on one side, and people accepting even a military coup - if it [would] end AKP rule on the other," he told Al Jazeera.

A veteran Turkish journalist, Avni Ozgurel, said deepening social polarisation served the interests of some politicians, especially of the opposition. "This case and the verdicts will be on Turkey's political agenda for a long time, and they will not be forgotten," Ozgurel told Al Jazeera.

"There may have been inequity, unfair accusations, [and] procedural faults throughout the case - but we cannot ignore the efforts to topple the elected government steadily melting with the impact of this case."

Point of contention

The life sentence handed to the former military chief has been one of the most discussed elements of the case since Monday's verdict.

The evidence against Basbug, who was charged with "attempting to overthrow the government using force and violence", consisted of a military document ordering the creation of websites to serve as propaganda against the government. However, it later came out that the websites in question had never been launched.

"Among his colleagues, Ilker Basbug was the one who had made the strongest emphasis on democracy in his speeches that I have heard," Ozgurel said. "Therefore no-one would expect me to believe that he was [planning] to topple the government or a member of a terrorist organisation.

"I think he troubled himself while trying to shade the wrongdoings of officials who were working under him."

Professor Sen also was also surprised with the sentence given to Basbug. "This person has served the president and the prime minister of this country in the highest security authority for two years. If his actions to overthrow the government were not detected within these two years, it is a pity," he said.

Failure to expose deep-state

The Ergenekon investigation was initially welcomed by much of Turkish society as an effort to curb the capabilities of the country's "deep-state"; an underground establishment with links to organised crime believed to be acting as an illegal state within the country - using assassinations and threats of extortion to pull the strings of power.

But questions mounted as the investigation targeted popular opposition figures, journalists, trade unions and non-governmental organisations. Concerns increased further after judges restricted the abilities of suspects to defend themselves in the trials.

PKK warns Turkey over reforms

Testimony from a large number of anonymous witnesses played a crucial role in the prosecution's case, generating public dissatisfaction in some quarters.

Revelations from an anonymous witness, who is thought to be a former Kurdistan Workers Party (PKK) leader, was one of the most controversial elements of the Ergenekon trial. An armed group, the PKK has been fighting against the Turkish army since 1984, though peace talks are currently underway.

Given alleged problems with the trial, many observers believe the judgement meant Turkey missed the opportunity to tackle problems with the "deep state".

"Even [though] some defendants were allegedly connected with organised crime, the proceedings failed to expose their link with bureaucractic and governmental organisations," Ozgurel said. "It [the trial] might have harmed this deep-state structure, but did it [cause enough] harm [that] it cannot recover again?"

Calislar agreed that judges and prosecutors failed to expose the allegedly criminal behind-the-scenes machinations of political life. "But we should not forget - since the trial started in 2008, we have not witnessed a single political assassination," he added.

Follow Gokhan Yivciger on Twitter: @gokhanyivciger

Source: Al Jazeera