At first during the movie head of state he would read a script written for him by someone else that had what everyone wanted to hear written on it, instead of what he actually believed. This is what most presidents do (besides Reagan) because they want to get the vote of the largest croud of people, the white middle working class Americans. But Chris rock wanted to get the vote of something he knew, something he believed in. So he decided to speak his mind and collect the vote of the African American ghetto and the African American people. He became a candidate because they wanted someone who would lose the election. And he became his own candidate when his brother told him to say what he believes instead of what he's told to say. He also wanted to impress the girl from "lots O' Gas"