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...