Michelle Obama warned men wary of voting for Kamala Harris not to make women “collateral damage to your rage” in an emotional speech in Michigan on Saturday evening.
The former first lady’s late appearance on the campaign trail comes as polls show Ms Harris virtually tied with Donald Trump in the White House race.
Mrs Obama, 60, said she was “angry” and “frustrated” the presidential election remained so close just 10 days before election day.
Speaking in Kalamazoo, Michigan, she made a direct pitch to male voters, among whom Trump has a significant advantage in the polls.
She said: “Fellas, before you cast your vote, ask yourselves: what side of history do you want to be on?”
“It is reasonable to be frustrated,” she continued. “But to anyone out there thinking about sitting out this election or voting for Donald Trump… let me warn you, your rage does not exist in a vacuum.”
“Your wife, your daughter, your mother, we as women will become collateral damage to your rage,” she added.
Scathing attack
She unleashed a scathing attack on Trump, accusing him of “gross incompetence”, “erratic behaviour”, and “obvious mental decline” and pointed out his record as a “convicted felon”, who had been “found liable for sexual abuse” in a civil case.
Her speech at a hockey arena in the city was met with rapturous applause and marked her first joint appearance with Ms Harris since the vice-president became the Democratic nominee.
In her own address, Ms Harris warned voters that Trump’s return to the White House would augur more “fear and divisiveness”.
She was a few minutes into speaking when she was heckled by a protester who yelled: “No more Gaza war.”
The state’s large Arab-American and Muslim population, frustrated by US inaction over the high civilian death toll of Israel’s bombardment of Gaza and Lebanon, could cost Ms Harris the key battleground.
Trump made his own appearance in the Midwestern state on Saturday, where he appealed directly to Muslim voters at a rally outside Detroit, arguing he would bring peace to the Middle East. “That’s all they want,” he said.