Social media battle lines drawn ahead of Turkish vote

(Repeats story published on Friday)

* Erdogan rides nationalist wave after coup, attacks

* 'Yes' vote cast as defending a "strong Turkey"

* 'No' campaigners say they are smeared as traitors

* Official campaigning to begin within weeks

By Ercan Gurses and Ayhan Uyanik

ANKARA/ISTANBUL, Jan 30 (Reuters) - Campaigning has not officially started, but a string of video "selfies" by the likes of sports stars, actors and cabinet ministers has already launched a divisive debate on plans that would hand Turkish President Tayyip Erdogan sweeping new powers.

His supporters see the move to replace Turkey's parliamentary democracy with an all-powerful presidency as a guarantee of stability at a time of turmoil. Opponents fear a lurch towards authoritarianism if an April referendum approves the change.

In a country where mainstream news channels are saturated by Erdogan's appearances and speeches by government ministers, and where political demonstrations are tightly restricted, the battle for votes is increasingly being waged online.

"Unfortunately the 'No' supporters don't have much opportunity to get their message across on television channels or other media," said actor Baris Atay, who was castigated by pro-government newspapers for a social media video in which he says "no to one-man rule, fascism and dictatorship".

"Saying 'Yes', siding with Erdogan, and being a nationalist is thinking of the country's future, but saying 'No' is being a provocateur, a traitor and a terrorist - this is the perception they're trying to establish," he told Reuters.

Atay's video was re-tweeted 23,000 times.

Against a backdrop of bombings by Islamic State and Kurdish militants, a failed coup last July, and the sharpest economic slowdown in almost a decade, Erdogan has cast Turkey as under attack and in need of stronger leadership.

The reform would enable the president to issue decrees, declare emergency rule, appoint ministers and senior state officials and dissolve parliament - powers that the two main opposition parties say strip away balances to Erdogan's power.

His supporters dismiss such claims and see the issue as a test of patriotism.

"Our homeland, our country is passing through a very tough period. A veritable war of independence. We want a strong Turkey. For a strong Turkey, yes, I am in," Ridvan Dilmen, the country's best-known soccer pundit, said in a video message on Twitter, triggering a chain of celebrity reactions.

"Coach Ridvan, I got your call. I'm in for a strong Turkey too," said soccer star Arda Turan, who plays for Barcelona, in a similar post, drawing 10,000 re-tweets in the soccer-mad nation.