Harris could become the first woman president after years of breaking barriers

Vice president Kamala Harris (Alex Brandon/AP)

She has already broken barriers, and now Kamala Harris could shatter several more after President Joe Biden abruptly ended his re-election bid and endorsed her.

Mr Biden announced on Sunday that he was stepping aside after a disastrous debate performance catalysed fears that the 81-year-old was too frail for a second term.