“If we lose Istanbul, we lose Turkey,” President Recep Tayyip Erdogan opined a couple of years ago over the political fortunes of his Justice and Development Party (AKP).

On June 23, Erdogan and his party suffered a historic debacle in the rerun of the mayoral race in Istanbul. Binali Yildirim, an AKP heavyweight who ran as the candidate of the People’s Alliance between the AKP and the Nationalist Movement Party (MHP), was outstripped by 806,000 votes by Ekrem Imamoglu of the main opposition Republican People’s Party (CHP). Imamoglu, who ran as the candidate of the Nation Alliance between the CHP and the right-wing Good Party, clinched 54.21% of the vote, boosted by decisive backing from the base of the pro-Kurdish Peoples’ Democratic Party. Yildirim trailed behind with 45%, a share that signifies a big loss of votes for Erdogan and the AKP in Turkey’s biggest city.

Yielding to pressure from Erdogan, the Supreme Electoral Council had canceled the original March 31 vote, which Imamoglu won by a margin of 13,000 votes. Erdogan argued at the time that “an election victory by such a tiny margin will not set the people’s mind at rest” and that “no one should put on airs as a winner with a lead of just 13,000 to 14,000 votes.” His own argument can now explain why he lost big time in the rerun. Had he stomached a defeat by “a tiny margin” of 13,000 votes on March 31, he would not have lost by a margin of 806,000 votes on June 23.

Erdogan’s setback amounts to a political earthquake. The June 23 result is nothing less than a tectonic shift in Turkish politics, the impact of which was felt in all of Istanbul’s districts. Imamoglu increased his vote in all 39 districts, while Yildirim saw his vote decline across the city, barring only one district.