In historic referendum, Turkey's Erdogan faces his biggest test
The vote, in which millions of Turks will decide whether to replace their parliamentary democracy with an all-powerful presidency, may bring the biggest change in their system of governance since the modern Turkish republic was founded on the ashes of the Ottoman Empire almost a century ago.
The outcome will have repercussions beyond Turkish shores.
The campaign has split the country of 80 million down the middle, its divisions spilling over to the large Turkish diaspora in Europe. Erdogan has accused European leaders of acting like Nazis for banning rallies on security grounds, while his opponents overseas say they have been spied on.
Erdogan's fervent supporters see his drive for greater powers as the just reward for a leader who has put Islamist values back at the core of public life, championed the pious working classes and delivered airports, hospitals and schools.
Opponents fear a lurch toward authoritarianism under a president they see as addicted to power and intolerant of dissent, chipping away at the secular foundations laid by modern Turkey's founder, Mustafa Kemal Ataturk, and taking it ever further from Western values on democracy and free speech.