As Turks prepare to vote in a referendum that would greatly expand the powers of President Recep Tayyip Erdogan, the advocates of the change are brimming with confidence while opponents say they don't know how to prevent the advent of one-man rule. The referendum will take place under a state of emergency that has been in place since last summer's failed coup which has seen some 47,000 arrested in the biggest crackdown in Turkey's history. A rejection of Erdogan's proposed constitutional amendments would keep alive the prospect that once this president is no longer in office, Turkey can finally have a shot at curbing the power of its rulers and, perhaps someday, making way for representative, inclusive democracy.
The "yes" vote would mean approval of constitutional changes that would replace the parliamentary system with a presidential one.
"Sunday will be a turning point in the fight against terrorist organizations".
The HDP was due later Saturday to hold a final mass rally in its stronghold of Diyarbakir in southeast Turkey.
The vote positions Erdogan's political base spanning the country's vast rural heartland against cosmopolitan antagonists in the Istanbul - a global crossroads for centuries.
"Please just think about it", said Abdullah, one of sixteen Turks who shared their views on the referendum.
"Tomorrow is very important", he told the crowd, reported Reuters. "Don't forget that the vote is our honour".
Pollsters have suggested a tight race, and fierce campaigning will continue until a ban comes into effect at 18:00 local time (15:00 GMT) tonight, with voting getting under way in the country's east at 07:00 local time (04:00 GMT) on Sunday and an hour later elsewhere.
More than one million Turkish immigrants live in Germany and the Netherlands, and have been eligible to submit postal votes. He has ridden a wave of patriotism since an abortive coup in July, casting Turkey as at peril from a cocktail of outside forces and in need of strong leadership to see off threats from Islamic State, Kurdish militants, the enemies within who tried to oust him and their foreign backers.
But Erdogan is a right-wing nationalist in the same vein as non-Muslim leaders like Russian President Vladimir Putin or Indian Prime Minister Narendra Modi.
The leader of the opposition Republican People's Party (CHP) Kemal Kilicdaroglu has called for a "No" vote, arguing there was too much uncertainty over the consequences of the new system.
Supporters say a "yes" vote would streamline and modernise the country; opponents fear the move would lead to increasingly authoritarian rule.
Erdogan, who has dominated the airwaves in recent weeks with multiple daily rallies and interviews, was due to give four more speeches in Istanbul.
The campaign has split the country of 80 million down the middle, its divisions spilling over to the large Turkish diaspora in Europe. He's sought to fix his relationship with Russian President Vladimir Putin - a staunch ally of the Syrian regime of Bashar al-Assad that Erdogan opposes - while threatening to reconsider ties with the European Union, a bloc Turkey had been trying to join for half a century.
"Legitimate dissent and criticism of government policy are vilified and repressed", Council of Europe's human rights commissioner, Nils Muiznieks, warned about the impact of emergency rule ahead of the campaign.