Barack Obama is hitting the Harris campaign trail this evening with a rally in Tucson, Arizona.

It comes after the former president caused controversy last week after making an appearance in Pennsylvania in which he admonished black men for their failure to support Ms Harris and suggested sexism might be at play.

“Part of it makes me think — and I’m speaking to men directly — part of it makes me think that, well, you just aren’t feeling the idea of having a woman as president,” Mr Obama said.

His appearance in Arizona, one of seven key swing states in this election, comes as Ms Harris has deployed a number of her most powerful surrogates, including former president Bill Clinton, with fewer than 20 days to go until the election.

The vice president will appear alongside the former president in Georgia on October 24, and with the former first lady Michelle Obama in Michigan on October 26.