the two supreme leaders since the revolution saying vote for them. the supreme leader is so central to this election. how much sway does he have over it? >> he's got a lot of sway. iranians are going to be voting for a president tomorrow, but looming very large over this entire process is the supreme leader ayatollah how maini. very few things gets done without his approval. in the race for iran's presidency, the one vote that matters more than any other, analysts say, is this man's iran's supreme lead e. ayatollah ali humani. it's the highest political and overseeing judiciary and foreign policy.