Mr Rafsanjani, still a power-broker as head of two bodies that are meant to adjudicate between branches of government, took the unusual step of firing off a long, heated public letter to Mr Khamenei, declaring that unless the supreme leader acted to ensure a fair vote, trouble would ensue.

ECONOMIST: Iran's election

To ensure that no person or group would amass too much power, the founders established a government in which the powers to create, implement, and adjudicate laws were separated.

WHITEHOUSE: Our Government