FINGERS CROSSED! Turkey’s Referendum Could Backfire on Erdogan.

Only one campaign is in sight less than a month before the April 16 referendum that would give Turkey’s President Recep Tayyip Erdogan vast new powers.

Building-size billboards feature a giant likeness of Mr. Erdogan urging the nation to vote “Yes.” On TV networks, government officials brand those opposing this executive presidency plan as traitors or supporters of terrorism. Finding any evidence of the “No” campaign can be mission impossible.

And yet, despite such a charged environment, a referendum victory for Mr. Erdogan looks surprisingly uncertain. Opinion polls keep showing a nation starkly divided along the middle—with a significant part of Mr. Erdogan’s own Justice and Development Party, or AKP, electorate balking at the idea of scrapping Turkey’s tradition of parliamentary democracy.

“This is a huge problem for them: they were thinking they will easily get 60%,” says Etyen Mahcupyan, a political consultant who served as adviser to former Prime Minister Ahmet Davutoglu, a leading figure in AKP. “And if we have a surprise on election day, it will be to the benefit of the ‘No’ vote. The government has created a ‘Yes’ atmosphere and many people are afraid of admitting that they will vote ‘No,’ and are not telling the truth to the pollsters.”

The referendum is the last chance for Turkish voters to turn back from the abyss, but fortunately this has been a time of electoral surprises.