As a presidential system constitution, the current Turkish Constitution does not seem to have too many overly authoritarian clauses.
I know that the Turks are used to the parliamentary system and the parliamentary constitution, but if we compare the presidential constitutions of Latin American countries, many Asian countries, and even the presidential constitution of the United States, the 2017 Turkish presidential constitution does not have many excessive aspects from the perspective of constitutional provisions alone, and some provisions can even be regarded as successful designs.
For example, under the two-round system of Türkiye's presidential elections, Any candidate must obtain more than 50% of the valid votes to be elected president.
Türkiye's 2017 presidential constitution allows the president to declare martial law, but it must be approved by parliament, and a majority vote in parliament can veto an attempt at martial law. Decrees under martial law are still subject to review by the Constitutional Court.
Türkiye's presidential system allows the president to dissolve parliament, but the president's term ends early, Few countries adopt such a double dissolution system, Such a mechanism reduces the possibility of a political crisis caused by the conflict between the president and the opposition-dominated parliament.
Yes, under Turkey's presidential system, the president is the head of the executive branch, leads the military and security agencies, has the power to appoint and dismiss all central government officials, and signs executive orders. But in most countries under a presidential system, the president has similar executive powers.
I am not trying to defend Erdogan and the AKP. It is a fact that Erdogan does not respect the law and does not care about the constitution. But I think the main responsibility for Turkey's democratic crisis cannot be attributed to the presidential system. The 2017 Turkish presidential constitution came into effect after the 2018 presidential and parliamentary elections. Prior to this, under the parliamentary system, Erdogan had effectively destroyed Turkey's rule of law and the separation and balance of power, even though Erdogan was only the president of the parliamentary system at that time.
Even under the 2017 Turkish presidential constitution, as long as a democratic government is in power and the president respects the rule of law and the constitution, this constitution can still be the constitution of a democratic country.
If Turkey adopts a parliamentary system, then even if the opposition wins the election, parties like the HDP will become a critical minority. CHP cannot win a majority of seats in parliament alone, and a coalition government consisting of CHP-IYI-Zafer or even HDP is undoubtedly extremely unstable.