that is the country's supreme leader ayatollah howmaini. he has more sway in this country than any of the nominees. reza, the ayatollah, i saw one woman she had basically a necklace around her neck with 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? >> reporter: 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 howmaini. very few things gets done without his approval. analysts say that includes the outcome of tomorrow's vote. 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 going to be difficult for any candidate whoksn't approved by the supreme leader to be elected president. >> reporter: he's the highest political and religious authority, overseeing the armed forces, judiciary and foreign policy. he also has fina