This study analyzes electoral engineering, which the Turkish government initiated before the June 2018 parliamentary elections. While the previous electoral law required each party to pass a 10% threshold for representation in the parliament, the Erdogan administration introduced a coalition rule in which parties could form an electoral coalition and face a joint threshold for the coalition. The law was initiated because of polls indicating that the political party, which helped the governing Justice and Development Party (AKP) pass a constitutional referendum, would not clear the 10% threshold by competing alone, and enabled it to coalesce with AKP. By using a formula designed by Flis, Slomczynski, and Stolicki, my simulations show that AKP actually lost approximately 28 seats due to the new coalition law by winning only 295 seats instead of the majority of 323 seats out of 600 in the old system. Moreover, the AKP's coalition partner received more than 10% of votes by itself. I discuss the factors that contributed to this spectacular mistake in electoral engineering.
