Proponents of a raft of deep constitutional changes that would transform Turkey from a parliamentary to a presidential system of governance claimed victory late Sunday night, with just over 51.2 percent of the vote amid record-high turnout, according to unofficial numbers released by state television and official news agencies. The country’s high electoral board confirmed victory for Erdogan’s “Yes” camp. . . .

The outcome was complicated by the narrow margin of victory, and the opposition’s allegations of voting irregularities. Turkey’s electoral commission announced at the last moment that it would accept ballots that lacked an official stamp, a change that prompted the country’s secular opposition People’s Republican Party to announce its intention to contest up to 2.5 million votes.

In many ways, a shaky outcome following a divisive campaign and allegations of political repression was the worst possible scenario for Turkey, suggesting that there’s a large and potentially destabilizing bloc of people in opposition to changes that include granting any popularly elected president the authority to issue decrees, name cabinet members, and declare a state of emergency and take unspecified national security measures without parliamentary approval.