Source: CBS / CBS Vice President Kamala Harris only had 107 days to try to become the President of the United States of America after her President, Joe Biden, withdrew as the Democratic candidate amid growing concern about his health and mental condition. Her new book, titled by that short window of time, 107 Days, details the behind-the-scenes of the shortest presidential campaign in American history. Source: Andrew Harnik / Getty From the moment she was essentially granted the opportunity to replace Biden in the race, VP Harris was the overwhelming underdog.