|Turkish constitutional referendum, 2017|
|Referendum to approve 18 proposed amendments to the Constitution of Turkey|
|Location||Turkey and overseas representations|
|Date||Sunday, 16 April 2017|
|Invalid or blank votes||862,251||1.73%|
|Results by province|
A constitutional referendum was held throughout Turkey on 16 April 2017 on whether to approve 18 proposed amendments to the Turkish constitution that were brought forward by the governing Justice and Development Party (AKP) and the Nationalist Movement Party (MHP). If approved, the office of the Prime Minister would be abolished and the existing parliamentary system of government would be replaced with an executive presidency and a presidential system. The number of seats in Parliament was proposed to be raised from 550 to 600 while the president was proposed to be given more control over appointments to the Supreme Board of Judges and Prosecutors (HSYK). The referendum was held under a state of emergency that was declared following a failed military coup attempt in July 2016.
Early results indicated a 51–49% lead for the "Yes" vote. In an unprecedented move, the Supreme Electoral Council (YSK) allowed non-stamped ballots to be accepted as valid. The main opposition parties decried this move to be illegal, claiming that as many as 1.5 million ballots were unstamped, and refused to recognize the results. Large-scale pro-democracy protests erupted following the results in order to protest the YSK's decision. In subsequent reports, the Organization for Security and Co-operation in Europe (OSCE) and Parliamentary Assembly of the Council of Europe (PACE) both criticised unfairness during the campaign and declared the YSK's decision to be illegal.
An executive presidency has been a long-standing proposal of the governing AKP and its founder, the current President of Turkey, Recep Tayyip Erdoğan. In October 2016, the Nationalist Movement Party (MHP) announced its co-operation for producing draft proposals with the government, with the combined support of both AKP and MHP MPs being sufficient to put forward the proposals to a referendum following a parliamentary vote in January. Those in favour of a 'Yes' vote argued that the changes were necessary for a strong and stable Turkey, arguing that an executive presidency would bring about an end to unstable coalition governments that had dominated Turkish politics since the 1960s up until 2002. The 'No' campaign have argued that the proposals would concentrate too much power in the hands of the President, effectively dismantling the separation of powers and taking legislative authority away from Parliament. Critics argued that the proposed system would resemble an 'elected dictatorship' with no ability to hold the executive to account, leading effectively to a 'democratic suicide' and autocracy. Three days before the referendum, one of Erdoğan's aides called for a federal system should the 'Yes' vote prevail, causing a backlash from the pro-Yes MHP. Both sides of the campaign have been accused of using divisive and extreme rhetoric, with Erdoğan accusing all 'No' voters of being terrorists siding with the plotters of the failed 2016 coup.
The campaign was marred by allegations of state suppression against 'No' campaigners, while the 'Yes' campaign were able to make use of state facilities and funding to organise rallies and campaign events. Leading members of the 'No' campaign, which included many high-profile former members of the MHP such as Meral Akşener, Ümit Özdağ, Sinan Oğan, and Yusuf Halaçoğlu were all subject to both violence and campaign restrictions. The 'Yes' campaign were faced with campaigning restrictions by several European countries, with the German, Dutch, Danish and Swiss governments all cancelling or requesting the suspension of 'Yes' campaign events directed at Turkish voters living abroad. The restrictions caused a sharp deterioration in diplomatic relations and caused a diplomatic crisis between Turkey and the Netherlands. Concerns were also raised about voting irregularities, with 'Yes' voters in Germany being caught attempting to vote more than once and also being found to have been in possession of ballot papers before the overseas voting process had started. European election monitors said the vote did not meet international standards.