A crisis looms as the prime minister opposes Recep Erdogan's desire to be a superpresident.
An agreement would also boost the legacies of the presidents of both Iran and the United States.
The sands are shifting under the Arab kingdom's feet but the absolutist country is loath to adapt.
When in the past European governments have paid ransoms of whatever kind to free their nationals, they have been accused of letting the side down.
The collapse of negotiations over Iran's nuclear programme would be potentially cataclysmic.
The country’s president is all too aware of the consequences of the meltdown in relations between Russia and the West.
Erdogan is often categorised as a Western ally. This is a misperception. His vision of Turkey is of an emerging great power and regional leader.
Negotiators say a deal over the country's nuclear ambitions is at hand, but trust issues remain.
Turkish Prime Minister Recep Tayyip Erdogan has emerged even more belligerent towards his opponents before the nationwide municipal elections.
The US president tells his Russian counterpart his political strategy is a generation out of date.