When Iranians vote Friday for president, it will be an election unlike any other.
Clerics who hold supreme power in the Islamic Republic have allowed elections for decades.
But while the people vote, clerics and their allies make the rules. Those already in power choose who can run for office and limit what they do if elected.
Restrictions are tighter than ever after massive protests that followed a disputed election in 2009. In fact, the country has come to redefine the whole purpose of an election.