Democratic Presidential nominee Joe Biden has appeared alongside Kamala Harris for the first time since her nomination as his running mate in November's election.
She is the first black woman on a major presidential ticket in US history.
They accused Donald Trump of leaving his country "in tatters".
Harris criticised Mr Trump's handling of the economy and the coronavirus pandemic in a speech in Delaware.
She also said that the President "cares more about himself than the people who elected him".
The 55-year-old spoke after Mr Biden introduced her as a "smart" and "tough" woman who is a "proven fighter for the backbone of this country".
