Michelle Obama has been called the president’s secret weapon. On Monday night, she was Hillary Clinton ’s.  

Until the first lady took the stage, the Democratic National Convention’s opening night mostly had been defined by episodic jeering from supporters of the presumptive Democratic presidential nominee’s primary foe, Sen. Bernie Sanders, I-Vt. But Obama’s passionate endorsement of Clinton and jabs at Republican nominee Donald Trump were met with thunderous applause.  

Following an opening hour during which Clinton and Sanders delegates interrupted speaker after speaker by shouting each other down, Obama showed why many political strategists believe she will be a campaign-trail force as Clinton seeks to rally her base and attract independent voters in key swing states.  

Obama began speaking about her daughters and the lessons they drew from watching campaigns.  

“In this election, and every election, is about who will have the power to shape our children for the next four to eight years of our lives,” Obama said. “And I am here tonight because in this election there is … only one person who I think is qualified to be president. And that is our friend Hillary Clinton.”  

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Special Coverage: 2016 Democratic National Convention
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For the first time all night, the Wells Fargo Arena crowd erupted in loud applause, many in attendance standing and cheering — though there were some audible boos from the Sanders camp.  

She lauded Clinton’s early career as a lawyer, when she was an advocate for children with disabilities, and for children in general throughout her career.  

Obama also had a not-so-veiled message for the Sanders backers: “When [Clinton] didn’t win the nomination eight years ago, she didn’t get angry or disillusioned.”  

“Hillary did not pack up and go home,” the first lady said, because “Hillary knows this is bigger than her own desires and disappointments.”  

(In other words: Stop protesting and start campaigning.)  

But Obama received the loudest cheers when she went after the GOP nominee, though she never used his name.  

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She said Clinton realizes that big issues are not “black and white” and cannot be “boiled down to 140 characters,” a clear swipe at Trump’s tendency to use Twitter to communicate attacks on foes and announce new — though typically vague — policy pronouncements.  

“When you have the nuclear codes at your fingertips and the military at your command, you can’t make rash decisions … or lash out,” Obama said, describing a commander in chief ’s necessary qualities as “steady” and “well informed.”  

She then pivoted back to Clinton, saying the likely Democratic nominee has a “record of public service” and would be a president who shows American children “we don’t chase fame.” Instead, she said a Clinton presidency would teach kids “we give back even when struggling ourselves b/c there’s someone always worse off.  

“Because of Hillary Clinton, my daughters … now take for granted that a woman can be president of the United States,” she said. “Hillary understands that the presidency is about one thing and one thing only — it’s about leaving something better for our kids.  

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“In this election,” the first lady said, “I’m with her!”  

In a theme she might repeat on the campaign trail, Obama noted she, a black woman, “wakes up every morning in a house that was built by slaves.” She often watches her two African-American daughters “play with their dogs on the White House lawn.”  

“Don’t ever let someone tell you this country isn’t great,” she said. “Because right now, this is the greatest country on earth.  

“We cannot afford to be tired or frustrated,” Obama said, again appearing to speak directly to Sanders’ delegates. “Need to do what we did four years ago and eight years ago. We need to knock on every door and get out every vote.”  

Contact Bennett at johnbennett@cqrollcall.com. Follow him on Twitter @BennettJohnT.