Editor's note: Cynthia Tucker, a Pulitzer Prize-winning syndicated columnist, is a visiting professor at the University of Georgia.
(CNN) -- After Michelle Obama's speech Tuesday night, it will be very difficult for her critics to portray her as angry or aggrieved. She rarely raised her voice. She smiled, she charmed, she seemed to tear up. She said not an unkind thing about her political opponents. Indeed, she never mentioned them.
Yet she eviscerated Mitt Romney and everything he represents by stunning contrast, by recounting her modest upbringing and reminding her audience that President Obama shared her unassuming roots. It was a bravura political performance cloaked in an apolitical narrative.
After Tuesday night, it will be very difficult for the Rush Limbaugh League to accuse the first lady of being unpatriotic, of failing to sufficiently love America. From her introduction by one of the nation's military supermoms -- Elaine Brye, mother of four military officers -- Obama spoke of schoolteachers, of firefighters, of wounded warriors and their sacrifices. Given Romney's failure in his convention speech to even acknowledge men and women in uniform, Obama's salute to them was another striking contrast, served up without venom or bile.
From their first presidential campaign, Michelle Obama's role has been at least as difficult to navigate as her husband's. As the first black woman to represent the country in a job with few defined duties but generations of cherished symbolism, she has had to endure relentless vicious attacks. She has been caricatured, as she has noted, as an "angry black woman."
She has been cast as hostile to whites. And her campaign against childhood obesity has earned cruel denunciations from the right, including a remark from an overweight GOP lawmaker that she has a "large posterior."
She has had to suffer through that privately, never shedding her calm exterior in public. She has had to shield her children from scrutiny and attempt to ensure they enjoy something close to normality. And she has had to carve out an official portfolio of suitable causes. But she has done all that with aplomb, racking up an enviable approval rating.
If she was once a reluctant political wife, she seemed Tuesday night to have found a way to enjoy her role. She was relaxed and confident. She was warm and approachable. (She was also lovely. That shouldn't matter, but it does. Just ask any woman in the national political spotlight.)
She wove a narrative thread around her insecurities about how the pressures of life in the White House might change her husband and her family. And she delivered a resounding assurance that the president remains not only loving and compassionate but also grounded in honesty and integrity. He can make the tough calls.
"Well, today, 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."
In a speech full of great lines, that was my favorite. If Romney is a congenital flip-flopper whose views shift with the political winds, Obama's character has already been revealed, she noted without rancor or even explicit comparison.
"And 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," she said.
Rarely have I heard a political speech that so deftly hit all the right notes and so stirringly found all the right chords.
She deftly deflected Republican accusations of class envy:
"Our families weren't asking for much. They didn't begrudge anyone else's success or care that others had much more than they did. ... In fact, they admired it."
But she also noted that Democrats don't believe in Ayn Rand's hyperindividualism.
"We learned about gratitude and humility -- that so many people had a hand in our success, from the teachers who inspired us to the janitors who kept our school clean ... and we were taught to value everyone's contribution and treat everyone with respect."
This was red meat served up in a bed of lovely salad greens from Obama's garden. Who could argue that wasn't a fitting entree from a First Lady?
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The opinions expressed in this commentary are solely those of Cynthia Tucker.