Joe Biden is unlikely to step aside from the US Presidential Election. There are calls for him to stand down after he stumbled answering questions and didn't finish sentences in the debate with Donald Trump. Many were calling it Biden's chance to prove his physical and mental fitness for another Presidential term. Canterbury University Political Science and International Relations professor Alex Tan says it would be messy for a new presidential candidate to step in. "There are others that could, but I'm not sure any of them would want to go into a situation like that." LISTEN ABOVE See omnystudio.com/listener for privacy information.