Former Obama adviser says Biden has not quelled voters’ age concerns

David Axelrod says it's a very hard case to make that anyone should be elected US president at the age of 82'

David Axelrod, a former senior adviser to Barack Obama, has warned that Joe Biden has not done enough to relieve voters' concern about his age since last month's disastrous debate.

Axelrod spoke to the Guardian in Milwaukee as US representative Adam Schiff became the highest-profile Democrat to call for the president to drop his re-election bid.