Can Kamala Harris as vice-president be both loyal deputy and heir apparent?

Harris says her model will be Biden's role as veep to Obama but the president-elect's age means speculation about an eventual elevation to the Oval Office is intense

American vice-presidents occupy what can be one of the most powerful positions in all of the federal US government and yet it can also be one of the least powerful. Vice-President-elect Kamala Harris is going to soon find out where her tenure will land.