First lady Michelle Obama began by recalling a day, not all that long ago, when she had resisted the idea of ever standing on that stage. But by the time she was finished with her opening-night address, Democratic National Convention-goers were asking themselves: What will her famously eloquent husband say on Thursday that could possibly top this?

That Michelle Obama made it look so effortless also made it easy to forget how long her journey has been, from a reluctant, sometimes controversial campaign spouse to one of the most admired figures in political life today.

Her address also reflected a real­ization by Obama and those around her that, for all its power, adulation is a most fragile thing. It must be treated tenderly when venturing into the rough terrain of politics. But Obama managed to navigate the chalk line, maintaining her above-the-fray aura while landing blows against her husband’s opponent.

The first lady also acknowledged that her husband’s first term has been difficult.

“After so many struggles and triumphs and moments that have tested my husband in ways I never could have imagined, I have seen firsthand that being president doesn’t change who you are — it reveals who you are,” she said.

Without naming GOP nominee Mitt Romney, she took a shot at his chief selling point, which is that his career in business is the best preparation for steering the nation out of hard economic times.

“I’ve seen how the issues that come across a president’s desk are always the hard ones, the problems where no amount of data or numbers will get you to the right answer, the judgment calls where the stakes are so high and there is no margin for error,” Obama said. “At the end of the day, when it comes time to make that decision, as president, all you have to guide you are your values and your vision and the life experiences that make you who you are.”

The easy part Tuesday night was reprising what she had done four years before at the Democratic National Convention in Denver, when many Americans got their first extended look at their first-
lady-to-be. That year and this, Obama narrated the history of a thoroughly American family, with a thoroughly American story.

Both she and Barack Obama came from the kind of people who “simply believed in the fundamental American promise that, even if you don’t start out with much, if you work hard and do what you’re supposed to do, then you should be able to build a decent life for yourself and an even better life for your kids and grandkids.”

It was impossible to miss the contrast she was trying to make when she said, “For Barack, success isn’t about how much money you make — it’s about the difference you make in people's lives.”

Just as important a mission for the first lady was rekindling the romance with those who supported her husband in 2008 but may be wavering now.

As she stood in line Wednesday to buy Obama paraphernalia outside the convention center, Angela Cureton of Waxhaw, N.C., called the speech “an altar call.”

“She hit it out of the ballpark,” said Cureton, 52. “She was passionate about taking the case forward and dragging people out of their homes and knocking them out of their complacency and reminding people of what they have to do.”

Michelle Obama’s rhetoric was well crafted, but much of its potency derived from her delivery, which shows the benefits of her four years of practice.

After a day in which speaker after speaker harangued from the stage, Obama managed to achieve something close to intimacy with a crowd of 15,000.

First lady is a role for which the Constitution provides no job description and yet one for which there is a set of expectations. In addition to being the first African American first lady, Obama also brings a set of distinctively modern contradictions — fashionista and fitness nut, a stay-at-home mom with two Ivy League degrees.

It was not always clear, least of all to the Obamas, that her ambitions and priorities would mesh with his.

In his 2006 book “The Audacity of Hope,” then-Sen. Barack Obama wrote candidly of the resentments that had grown during his early political career, when his wife was often left alone to manage the family and began to grapple with the realization that her professional goals would take a back seat to his.

“Leaning down to kiss Michelle goodbye in the morning, all I would get was a peck on the cheek,” he recalled. “By the time Sasha was born — just as beautiful, and almost as calm as her sister — my wife’s anger toward me seemed barely contained.”

Early in the 2008 presidential campaign, Michelle Obama struggled to find her footing. She raised eyebrows, and stirred the stereotypes of an angry black woman, when she declared that “for the first time in my adult lifetime, I am really proud of my country.” A New Yorker cover cartoon parodied the perception by portraying her as an armed and Afro-ed radical.

The movements that she has led as first lady, however, have been to raise healthier children and improve the quality of life for military families. And perhaps taking a lesson from Hillary Rodham Clinton’s searing experience with health care, she has steered clear of anything that resembles a policymaking role.

Her work at the convention did not begin or end with her speech. Just about everyone here, it seems, wants a chance to see her close up. Her schedule indicates that, by the time it is over, she will have made appearances before just about every constituency here: African Americans; gay, bisexual and transgender elected officials; women; Hispanics. On Thursday, she and Jill Biden, the vice president’s wife, will help put together packages of toiletries for service members overseas.

And she has delegates talking.

“I don’t consider it a speech,” said Michelle Davis of Palm Beach County, Fla. “I think it was a conversation that she had with the Democratic Party.”

She said she was most encouraged by Obama’s personal defense of the president’s accomplishments. “There are a lot of untruths out there about him and what he’s done,” Davis said. “And he’s done a whole lot for the American people.”

Several passersby complimented Davis on her T-shirt, featuring images of Oprah Winfrey, Jennifer Hudson, Rosa Parks, Coretta Scott King, Maya Angelou and Whitney Houston. Right in the center was Michelle Obama’s face.

“She’s in the middle because it’s her time,” Davis said. “All of these women have shared in their time, but right now, it’s Michelle’s time.”