WATCH LIVE: Harris speaks during the campaign rally with Michelle Obama in Kalamazoo, Michigan

KALAMAZOO, Mich. (AP) — Michelle Obama delivered a sharp indictment of Donald Trump in Michigan on Saturday and challenged voters to support Kamala Harris as the first female president of the United States.

Watch the event live in the player above.

“She has shown in every way that she is ready,” the former first lady said. “The real question is: are we as a country ready for this moment?”

It was Obama’s first appearance on the campaign trail since she spoke at the Democratic National Convention in Chicago last summer, and her remarks were powerful and passionate, even vulnerable.

She said she fears for the country and struggles to understand why the presidential race is still close.

“I lay awake at night wondering, ‘What the hell is going on?’” she said.

WATCH: How Harris and Trump are trying to reach voters in the battleground state of Michigan

Her voice shaking with emotion, Obama warned that Trump’s potential return to the White House would undermine women’s health and reproductive freedom.

“I ask all of you from the core of my being to take our lives seriously,” she said.

The meeting in Kalamazoo followed Harris’ visit to a local doctor’s office in Portage to talk to health care providers and medical students about the impact of abortion restrictions. One said she is seeing patients coming from other parts of the country where there are strict restrictions on abortion, and another said she is concerned that people will not want to practice in important areas of medicine for fear of government interference .

“We are looking at a health care crisis in America that affects people of every background and gender,” Harris told reporters before visiting the doctor’s office.

Meanwhile, President Joe Biden went to a union hall in Pittsburgh to promote Harris’s support for organized labor, telling the audience to “follow your gut” and “do what’s right.”

Harris appeared with Beyoncé on Friday in Houstonand she campaigned with former President Barack Obama and Bruce Springsteen on Thursday in Atlanta.

It’s a level of celebrity influence that surpasses anything Donald Trump, the Republican nominee, has managed to achieve this year. But there is no guarantee that Harris will help in the tight race for the White House. In 2016, Hillary Clinton lost to Trump, despite electrifying her audience with musical performances and Democratic allies.

Trump brushed off Harris’ attempt to leverage star power for her campaign.

“Kamala is at a dance with Beyoncé,” the former president said Friday in Traverse City, Michigan. Trump, the Republican nominee for president, was scheduled to hold a rally in the Detroit suburb of Novi on Saturday before a later event in State College, Pennsylvania.

WATCH: Trump bashes Detroit again as he asks for votes in Novi, Michigan

Saturday marks the first day early in-person voting became available across Michigan. More than 1.4 million ballots have already been submitted, representing 20% ​​of registered voters.

When Clinton ran against Trump, Michelle Obama inspired the Democrats with the slogan ‘when they go low, we go high’.

But this year she took a sharper approach at the Democratic National Convention in Chicago. She accused Trump of “doubling down on ugly, misogynistic, racist lies as a substitute for real ideas and solutions that will actually improve people’s lives.”

At a campaign event in Pittsburgh, Biden spoke to the Laborers’ International Union of North America. He said Harris once walked a picket line with the United Auto Workers — “she has a spine like a ramrod” — while Trump has undermined organized labor.

“He sees unions as an obstacle to the accumulation of wealth for individuals,” Biden said. “It is in Labor’s interest to beat Donald Trump more than any other race you have been in.”

Biden’s remarks to the predominantly male audience referenced the gender gap that has been a consistent feature of this year’s presidential race.

Biden said of Trump: “I’ll just say it straight: he’s a loser as a man.”

He also said women deserve more opportunities than they have received in the past.

“They can do anything any human being can do, including becoming president of the United States of America,” Biden said.

Madhani reported from Pittsburgh and Megerian reported from Washington.