Michelle Obama is bringing back her political star power to buoy support for Vice President Kamala Harris in the final sprint of the 2024 election.

In her first campaign appearance with Harris, the former first lady added a new argument in the fight reproductive health care, issuing a stark but passionate warning aimed at men in which she urged them not to let women become "collateral damage to your rage."

"I am asking y'all, from the core of my being, to take our lives seriously," she said at a rally in Kalamazoo, Michigan, on Saturday night.

Obama repeated that exact message in an op-ed published by the New York Times on Monday, and she is due back on the trail on Tuesday to headline a rally in battleground Georgia with her own nonprofit When We All Vote aimed at engaging young voters.

Obama has made clear her dislike of partisan politics, but came out to set the stage for Harris' historic nomination at the Democratic National Convention this summer.

After an extended standing ovation reflective of the immense popularity she wields not only within the party but around the country, the former first lady lifted up Vice President Harris while tearing apart Donald Trump.

The comments marked a departure from her once-famous political motto: "When they go low, we go high."

That theme continued in Michigan over the weekend, as Obama cast Harris as "someone with the strength of heart to guide our country to a better day" and Trump as someone unfit for the White House.

"In any other profession or arena, Trump's criminal track record and amoral character would be embarrassing, shameful and disqualifying," she said.

She then laid out what she saw as a double standard in this race.

"I hope you'll forgive me if I'm a little frustrated that some of us are choosing to ignore Donald Trump's gross incompetence while asking Kamala to dazzle us at every turn," she said. "I hope that you'll forgive me if I'm a little angry that we are indifferent to his erratic behavior, his obvious mental decline, his history as a convicted felon, a known slum lord, a predator found liable for sexual abuse."

"All of this," Obama continued, "while we pick apart Kamala's answers from interviews that he doesn't even have the courage to do."

Vice President Harris was asked on Monday about Obama's comments and if she felt she needed to meet a higher standard than Trump.

"My role and responsibility, running for president of the United States is to make my case to the American people and to earn their support, and that is why I'm spending time traveling the country to listen to folks and to talk with them about my plans," Harris responded.

A new ABC News/Ipsos poll found Harris regained a slight lead nationally in the polls over Trump, 51-47%. But the two remain neck-and-neck in the battleground states that will likely determine the winner of the election.

Polls also show a stark gender divide, as Trump leads with male voters and Harris with an advantage with women. Black voters and younger voters, too, are considered key voting blocs this cycle.

Obama's appeal to men in her speech this past weekend comes after her husband, former President Barack Obama, a key Harris surrogate, expressed his own frustration with Black men who he said didn't want to vote for Harris because she's a woman.

The former first lady, in a slightly different pitch, urged men to think about what impact their votes could have on the women in their lives.

"Please do not put our lives in the hands of politicians, mostly men, who have no clue or do not care about what we as women are going through, who don't fully grasp the broad-reaching health implications that their misguided policies will have on our health outcomes," she said in Michigan.

Her focus on Tuesday will be on turning out first-time voters and students, according to When We All Vote, the non-partisan civics group founded by Obama that's been working to register voters. The rally she will headline comes just before early voting ends in Georgia.

ABC News' Fritz Farrow, Gabriella Abdul-Hakim and Will McDuffie contributed to this report.