ISTANBUL -- Turkey is a country sharply divided ahead of a referendum Sunday that would greatly increase the Turkish president’s power. The country is a NATO ally and a key player in the fight against terror across its borders in Syria and Iraq.

This is no ordinary vote, it’s a turning point, President Recep Tayyip Erdogan tells his adoring base -- many of them poor, religious conservatives from the country’s hinterland.

He’s campaigning to weaken Turkey’s courts and lawmakers -- giving himself sweeping new powers.

Turkey will vote on April 16 on whether to increase President Recep Tayyip Erdogan’s power. CBS News

We trust him, Ayla Sik told us. And we’ll support him with our yes votes, God willing, she said.

But President Erdogan’s critics say this referendum could smooth the path for him to become a dictator.

There’s a new climate of fear in Turkey, which began nine months ago, when an attempted military coup came close to ousting President Erdogan from power.

In response, there was a mass purge of anyone Erdogan’s government views as an enemy. Around 50,000 have been arrested, including more than 2,000 judges and prosecutors, as well as journalists, university professors, doctors, a concert pianist and an American pastor who has lived in the country for 20 years.

Barbaros Sansal is a fashion designer who just spent two months in prison for posting comments online that offended the government.

Barbaros Sansal is a fashion designer who spent two months in prison for posting comments online that offended the Turkish government. CBS News

“One iron bed, one blanket, three steps by three steps, caged air, alone, totally alone,” he said in describing the conditions.

He was beaten by a pro-government mob in January and is so worried it’ll happen again, he rarely leaves his house.

That’s a pretty frightening thought in what is supposed to be a democracy.

“Democracy? I beg your pardon?” Sansal says. He says that Turkish democracy is “almost” finished.

In Erdogan’s new, 1,000-room presidential palace, he’s surrounded by the trappings of Turkey’s imperial past. Some here fear his real ambition is to become a modern-day sultan, for life.