Former Vice President Joe Biden named his former campaign trail rival, Sen. Kamala Harris, D-Calif., as his running mate.
Biden announced the decision in an email to supporters.
“I know a thing or two about being Vice President. More than anything, I know it can’t be a political decision. It has to be a governing decision. If the people of this nation entrust me and Kamala with the office of President and Vice President for the next four years, we’re going to inherit a nation in crisis, a nation divided, and a world in disarray. We won’t have a minute to waste. That’s what led me to Kamala Harris,” Biden said in the email.
Once a rival for the top job, the California senator of Indian-Jamaican heritage had long been considered the front-runner for the position.
The former California attorney-general has been urging police reform amid anti-racism protests.
Mr Biden will face President Donald Trump in the election on 3 November.
Vice-President Mike Pence remains the Republican incumbent’s running mate.
Only two other women have been nominated as vice-presidential candidates – Sarah Palin by the Republican party in 2008 and Geraldine Ferraro by the Democrats in 1984. Neither made it to the White House.
A woman of colour has never been appointed to a presidential ticket by either of the two main American political parties. No woman has won the US presidency either.