By Stephanie Irvine
BBC Eurasia editor
The army sees itself as the guardian of Ataturk's legacy
Why is the Turkish army so determined to defend secularism, the separation of religion and state?
Secularism is fundamental to Turkey's identity as a nation.
Turkey was founded in 1923 by Mustafa Kemal Ataturk, a military general, in what had been the Ottoman Sultanate.
Ataturk was determined that this mainly Muslim nation would be a modern, secular country, and he introduced wide-ranging reforms, including the emancipation of women, the introduction of western dress, legal code and alphabet, and the abolition of Islamic institutions.
Turkey's ruling elite and the powerful military have seen it as their job to protect what Ataturk set up.
The army has not been afraid to intervene militarily whenever it sees fit - it has led three direct coups against elected governments in Ankara.
When, 10 years ago, Turkey elected its first pro-Islamic party to government - the Welfare Party - the military campaigned to force it out of office. The following year the party was banned by the courts.
The staunchly secular elite of Turkey believes a president whose wife wears an Islamic headscarf would have Ataturk turning in his grave
But despite the efforts of the establishment, it seems that Islamic parties are popular in Turkey, and in 2002 the Justice and Development (AK) party of Prime Minister Recep Tayyip Erdogan won a landslide victory.
The party has its roots in political Islam, but insists it respects the secular principles of the constitution.
The army has tolerated its position in government, but the prospect of one of its members taking up the highest post in the land is causing it great concern.
The staunchly secular elite of Turkey believes a president whose wife wears an Islamic headscarf would have Ataturk turning in his grave.