First lady Michelle Obama addressed the crowd on the opening day of the Democratic National Convention in Philadelphia July 25. (Video: The Washington Post/Photo: Toni L. Sandys/TWP)

Michelle Obama had a full-circle moment onstage here Monday night. She began her remarks by remembering how young her daughters were when her husband was elected to the White House in 2008.

“When they set off for their first day at their new school, I will never forget that winter morning as I watched our girls, just 7 and 10 years old, pile into those black SUVs with all those big men with guns,” she said. “And I saw their little faces pressed up against the window, and the only thing I could think was, ‘What have we done?’ ”

Her daughters are nearly full grown, a sign of how much time has passed since the election cycle eight years ago.

Back then, the Obamas fought hard against the Clintons through an epic primary contest. There was no love lost between them. Even after Hillary Clinton took the job of secretary of state in the Obama administration, she and the new first lady did not forge a particularly close bond. Obama, in fact, seemed more connected with her Republican predecessor Laura Bush, with whom she formed a friendly relationship.

None of that awkward history impeded the first lady at the Democratic convention. In a prime-time spot on opening night, she spoke with unabashed warmth for Hillary Clinton and fully embraced her as the Democratic Party’s new standard-bearer. “This election,” she said, “I’m with her.”

“When she didn’t win the nomination eight years ago, she didn’t get angry or disillusioned,” Obama said. “Hillary did not pack up and go home, because as a true public servant, Hillary knows that this is so much bigger than her own desires and disappointments.”

It was a moment that could be read as a call to the supporters of Sen. Bernie Sanders who had protested bitterly all that day, disappointed that their candidate was not still contesting the nomination.

She continued: “There were plenty of moments when Hillary could have decided that this work was too hard, that the price of public service was too high, that she was tired of being picked apart for how she looks or how she talks or even how she laughs. . . . What I admire most about Hillary is that she never buckles under pressure.”

The remarks were in keeping with the first lady’s style of politics, focused on character and being a role model. She avoided all talk of specific policy proposals and tried to stay above the nitty-gritty of party politics.

Instead, she laid out her case against Donald Trump, pointedly without mentioning his name. She ascribed to the Republican nominee characteristics that contrast with the way she has described her husband — who she says is cool, evenhanded, caring. She referred to Trump as a birther, thin-skinned and ill-informed.

“I want someone with the proven strength to persevere, someone who knows this job and takes it seriously, someone who understands that the issues a president faces are not black and white and cannot be boiled down to 140 characters,” she said. “Because when you have the nuclear codes at your fingertips and the military in your command, you can’t make snap decisions. You can’t have a thin skin or a tendency to lash out. You need to be steady and measured and well-informed.”

She was one of the few Democratic speakers who attacked Trumpism without seeming to sling mud.

Obama has been criticized by Republicans as a proponent of “Nanny-state” policies — meddling with school lunches and telling Americans they should work out — but she rarely gets involved in partisan politics. For that reason, her popularity has remained relatively high. Nearly 60 percent of Americans say they like her. Her favorability with the Democratic base is even higher.

On big occasions, such as the party’s national conventions, she practices her remarks over and over. In the past, her husband has been the focus of her remarks. She spoke for less than 12 minutes about Clinton — but showed strong emotion when she did. Her voice caught as she spoke of the possibility of electing a woman to be president, comparing the chance with the history made by her husband as the first African American elected to the White House.

She convincingly tied Clinton’s campaign to her own story. “Today, I wake up every morning in a house that was built by slaves. And I watch my daughters, two beautiful, intelligent, black young women playing with their dogs on the White House lawn,” she said before praising Clinton as having the “guts and the grace to keep coming back and putting those cracks in that highest and hardest glass ceiling until she finally breaks through, lifting all of us along with her.”

Before Obama spoke at Wells Fargo Center, Clinton spokeswoman Jennifer Palmieri said she would be a “highly effective messenger” for the Clinton campaign. But the question going into Monday night remained: Would Michelle Obama be able to summon the passion she had expressed for her husband’s campaigns in 2008 and 2012 for another political candidate?

It was unclear how forcefully she would spend her popularity on pushing for Clinton’s election. Now, there is no doubt that she is all in.

Obama does not sound as if she is being coy when she denies having political ambitions for herself. She has been emphatic in saying that she will not run for public office. But on Monday night she gave Americans a glimpse of the kind of public figure she plans to be outside the White House: one who remains engaged in the nation’s civic life even once she and her husband are again private citizens.