Turkey votes today on whether to cement the power of a man revered by many, reviled and feared by many others

The boulevards of Istanbul are lined with posters backing both sides in today’s knife-edge referendum on constitutional reform. Both camps – “evet” (yes in Turkish) and “hayır” (no) – are convinced they hold the key to resolving the republic’s many troubles.

But one image dominates the debate. Recep Tayyip Erdoğan’s face is ubiquitous. In one poster, his steady gaze is accompanied by the caption: “For security, for stability.”

Millions of Turks will head to the polls today to vote on a host of amendments that will transform the nation from a parliamentary democracy into a presidential republic. Supporters of the bill say it will lead to a strong Turkey that will no longer be hampered by messy coalition politics, able to take great leaps of economic development and be freshly assertive on the world stage.

Opponents say it will set the stage for transforming the regime from a nominally democratic one into an autocracy or even dictatorship that rules by decree, cementing Erdoğan’s hold on power until 2029, because he will be able to remain in office until then if the referendum bill is approved and he wins successive elections.

Erdoğan has never lost an election during his extraordinary climb to power.

Born in 1954 in the impoverished and conservative neighbourhood of Kasımpaşa in Istanbul to a sea captain father, with family roots in Rize on the coast of the Black Sea, Erdoğan entered politics early. After studying at an İmam Hatip school, a vocational religious institution, and after a stint playing football at the local Kasımpaşa team, he went on to study at Marmara University’s business administration programme. He then joined the Islamist National Salvation party, heading its Istanbul youth branch, before it was closed after the military coup in 1980.

After he joined the Welfare party of the Islamist prime minister Necmettin Erbakan in the 1980s, he climbed the ladder in the party until he ran for the post of mayor of Istanbul, winning in 1994 and instituting reforms that improved the quality of life in the city. His mayorship lasted four years, at the end of which the Welfare party had been declared unconstitutional and banned.

He was imprisoned in 1999 over his recitation of a poem that included the verse: “The mosques are our barracks, the domes our helmets, the minarets our bayonets and the faithful our soldiers”, which the court decided was an incitement to violence.

After leaving prison, he founded the Justice and Development (AK) party, which continued to win landslide parliamentary election victories with him at the helm, until he was elected president in 2014 and, nominally, although not practically, severed his relationship with the party.

Erdoğan used that time wisely. He ushered in reforms that reined in inflation and led to massive economic growth, saw the launch of great infrastructure projects and provided assistance to the poor, such as better healthcare. Turkey became a key regional power and entered serious accession negotiations with the European Union.

He also took steps to deal with the Kurdish question, opening negotiations with the Kurdistan Workers’ party (PKK), the separatist group fighting an insurgency against the state in the south-east, culminating in a ceasefire deal and the lifting of restrictions on Kurdish cultural celebrations and language.

Today, the conflict with the PKK has resumed with ferocity. Terror attacks have racked Istanbul and Ankara, and Islamic State cells are dismantled on a weekly basis. Tourism has declined, while relations with the EU are at an all-time low. Rebels backed by the president have failed to unseat Bashar al-Assad in Syria and 3 million refugees have sought safe haven in Turkey amid the spiralling violence.

The constitutional reforms will further entrench the president’s power, allowing him to rule with almost no checks and balances, given the primacy of the ruling AK party in parliament, the party he will be able to head officially once again and choose its candidates in the elections. The reforms will allow him to appoint judges and will do away with the formality of holding his ministers accountable by removing the assembly’s ability to oversee them.

Cementing the president’s hold on power will go hand in hand with the wide-ranging crackdown he has led on dissidents, as well as those implicated in the coup attempt last July, a traumatic moment that claimed more than 200 lives. The numbers of those purged are staggering and hint at a broad attempt to reshape not just the bureaucracy, but society at large.

Facebook Twitter Pinterest Marchers in Istanbul urge voters to choose “no” in the referendum. Photograph: Ozan Köse/AFP/Getty Images

Tens of thousands of people have been fired from their posts in universities, the military and police, the judiciary and civil service. Nearly 150 journalists are in prison on various trumped-up charges, including abetting terrorism and conducting propaganda on behalf of terror organisations.

Many in the opposition say the new system will create a “tek adam” regime, a phrase often translated as one-man rule, but the word “tek” also means “only” or “single”.

The grip on the state’s institutions is a legitimate fear for the opposition and one that Erdoğan’s supporters have done little to allay because it has been a coalescing reality for much of the last decade. The president first purged the military of dissenting officers in the mid-2000s in large-scale trials, the notorious Ergenekon and Balyoz (Sledgehammer) affairs.

The state was then purged of followers of the movement of Fethullah Gülen, the exiled, US-based preacher whose acolytes in the bureaucracy, police and judiciary helped the AKP run the state, before falling out with the president and allegedly orchestrating the coup attempt last July.

When the AKP failed to win a convincing majority in the June 2015 parliamentary elections that would allow them to rule without a coalition, that supreme status was nearly upended. But the snap elections in November that year produced another clear majority, as violence escalated in the Kurdish south-east.

In the party’s victory rally, jubilant supporters in Ankara chanted: “AK parti, tek parti”, a celebration not so much of the party’s victory as of its renewed mandate to rule alone.

That is why the argument pushed by Erdoğan’s aides and lawmakers from his former party, that the reforms will put an end to the fractious coalition politicking that held the country back in the 1990s and led to hyperinflation and economic decline, strikes many observers as disingenuous. The AK party has had more than a decade of single-party rule.

Still, many supporters identify with the president, who sold lemonade and simit, a Turkish bread pastry, as a youngster in marginalised Kasımpaşa. They see in him an empowering figure, one who overturned the oppressive secular traditions and rule of the elite, the “White Turks”, Europeanised and disdainful towards the Islamic traditions of the Anatolian heartland.

Now, supporters say, they can wear their headscarves without fear or shame and espouse an Islamic identity without fear of censure. The president’s personal piety is a matter of great interest. A recent photo that showed him on the night of the coup attempt last July, teaching the Qur’an to his grandson, while they were holidaying in the resort town of Marmaris, quickly went viral, as well as a series of photos that showed him performing the lesser pilgrimage in Mecca after a state visit to the Saudi king.

He has also taken up as a personal crusade against smoking, which is at epidemic proportions among Turks. He will sometimes reprimand shopkeepers he meets on his tours for smoking, as well as close aides who have the habit.

While western academics and diplomats are fond of pointing out the failures of Turkey’s activist foreign policy in the region, the president’s faithful supporters often describe his victories as a triumph for the Middle East’s beleaguered citizens.

That image of an ally of the downtrodden is one Erdoğan has cultivated well, since his sudden outburst at a Davos summit panel with Israeli president Shimon Peres, when he condemned a recent offensive on the Gaza Strip. Erdoğan still enjoys a groundswell of popularity in the Arab world, even among those not of an Islamist bent, for his piety and declared support of various oppressed factions in society.

Erdoğan’s supporters have imbued him with a cult of personality rarely seen in the country since it was founded on the ashes of the Ottoman empire by Mustafa Kemal Atatürk. They propelled him to the presidency in 2014 in the first ever popular presidential elections in the republic’s history, a mandate that allowed him to reshape a largely ceremonial post into an influential one simply by sheer willpower.

A clear example is the constitutional amendments bill, in which the ruling party essentially voted for a proposal that would give away the powers of its lawmakers in parliament and abolish the post of its own prime minister in favor of empowering its founder as a powerful executive who can lead for the next 12 years if he wins the elections.

Members of the opposition insist that they are not fighting the referendum bill because of Erdoğan himself. They say the new system will create a de facto dictatorial regime, regardless of who is in power.

“It’s not a matter of Erdoğan, it’s a matter of being against this systemic change,” said Bülent Tezcan, a lawmaker at the opposition Republican Peoples’ party.

“If it’s [opposition leader] Kemal Kılıçdaroğlu, or me, or anyone who has all of these powers, they will become a dictator.”

But in a sense, all politics in Turkey is about Erdoğan. Turkish politics has often been dominated by oversize personalities who tried to reshape the state in their own image, from Ataturk to his successor, İsmet İnönü, to Adnan Menderes, Turgut Özal, Süleyman Demirel and Bülent Ecevit.

Now Erdoğan may be set to preside over one of the most important turning points in the history of the republic, crowning himself a leader of unrivalled power in Turkey’s recent history, towering over his predecessors.

THE ERDOĞAN FILE

Born 26 February 1954, the youngest of five children, in Kasımpaşa, a rundown district of Istanbul. He attended a religious school and as a teenager was a talented footballer and there was talk of him turning professional. At university, he met his mentor, Necmettin Erbakan, who would later become prime minister of Turkey.

Best of times Bringing Turkey years of economic growth – he spent 11 years as Turkey’s prime minister before becoming the country’s first directly elected president in August 2014.

Worst of times The attempted coup in July 2016, when a section of the Turkish military tried to unseat him. Tanks took to the streets and 240 people died.

What others say “Half of the country adores Erdoğan and half of the country loathes him.” Soner Cagaptay, Washington Institute for Near East Policy.

What he says “My reference is Islam… If I can’t reflect this, what is the reason for living? Nobody can silence the ezan [the Muslim call to prayer] because whenever it is silenced people have no peace.” Speech in which Erdogan also quoted a poem by Mehmet Ziya Gökalp, who was imprisoned for anti-secularism.