By founding principles, I mean the Article 4 of Turkey, which the current government is planning to abolish.
Those are (From Wikipedia):
The Article 4 declares the immovability of the founding principles of the Republic defined in the first three Articles and bans any proposals for their modification. The preamble also invokes the principles of nationalism, defined as the "material and spiritual well-being of the Republic". The basic nature of Turkey is laïcité (2), social equality (2), equality before law (10), the Republican form of government (1), the indivisibility of the Republic and of the Turkish Nation (3.1)." Thus, it sets out to found a unitary nation-state based on the principles of secular democracy.
Of course, what the present President-led government has in mind seems to be very different. Hence it abhors the secular state, its founder and all the related values.
The coup attempt appeared to be doomed to fail from the beginning. And it will produce a strongman the world has not witnessed in recent history -- sadly. Couple that strong man with a yearning for Ottomanist orthodoxy and Islamic Brotherhood-style theocracy. Very unfortunate.
The Palace will both de facto and de jure take over the whole government apparatus. Military will be violently purged. The Palace-supported police (including private security firms with ties with the current President) will gain upper hand and absolute control of civil life in Turkey.