Absolutely true. The "president" is a figurehead to lull Iranians into a false sense of having some freedom (it worked for a while but not anymore) and appease the Hillary Clintons into insisting Iran is "progressive". The mullahs have all the power. Nothing happens without their approval.
Supreme Ruler Ali Khamenei used to be "the man" till Ahmadi-Nejad became President and put his IRGC military commanders into all executive and military positions of power way down to middle and some lower level positions.
Both Khamenei and former Pres Rafsanjani risk being arrested by the new militarist power base for corruption and dereliction of duty toward Islam.
Can't count on any of them, nor the previous power structure, to have the will let alone the ability to counter Ahmadi-Nejad - short of killing him and his mentor Ayatollah Mesbah Yazdi. Ahmadi-Nejad holds all the trump cards for now and does not have to conform to the rules, though he may not be ready to have a civil war yet.