Koritha Mitchell is a literary historian and cultural critic who teaches at Ohio State University. She is author of the award-winning " Living With Lynching " and the forthcoming (in 2020) "From Slave Cabins to the White House: Homemade Citizenship in African American Culture." Follow her on Twitter @ProfKori . The opinions expressed in this commentary are her own. View more opinion articles on CNN.

(CNN) Polls now confirm it! Michelle Obama is the country's most admired woman. This recognition is about much more than looks, but they play a part.

In her record-setting memoir "Becoming," Mrs. Obama confesses to having been initially frustrated by the public's interest in her appearance as first lady. "It seemed that my clothes mattered more to people than anything I had to say," she explains. Over time, she found ways to make an asset of what she calls the "hawkeyed attention paid to my image."

The decisions Michelle Obama made in creating her public persona reveal how carefully she had to navigate a cultural landscape determined to confine women, especially women of color. Her facility for navigating racism and sexism has always drawn admiration from some Americans, especially black women, because their experiences at school, work and other realms have required the same of them.

Now, a larger swath of Americans has recently joined in this admiration. Perhaps witnessing the ascendency of Donald Trump's first family has led even the most skeptical to conclude that the "polarization" attributed to the Obamas always said more about the public than about them.

Mrs. Obama constructed her public image through such things as gardening and a commitment to military families and education, but because her time in the White House was also shaped by the public's interest in her looks, it was her hair choices that proved especially telling. And its importance cannot be underestimated.

As noted in "Becoming," FLOTUS is "not technically a job, nor is it an official government title." Nevertheless, the nation expects a first lady to represent American womanhood and inspire all women to identify with her. Because Mrs. Obama always wore her hair straightened and in a medium-length bob while in the White House, women of all backgrounds could ask their stylists to approximate the look, which was not particularly elaborate.

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If Mrs. Obama's hair had been kinky or coily -- terms used to describe the unstraightened hair texture of African- Americans -- or if it had been braided or locked, women of other racial or ethnic backgrounds may not have easily aspired to and achieved her style. One black woman -- even if she was the first lady -- was not going to spark a trend of white women requesting super-tight curly perms.

Given Western beauty standards, it was much more expedient for Mrs. Obama to wear her hair straight and therefore avoid having the majority of non-black women hesitate to consider whether they could achieve the first lady's look.

And even more than the question of achievability, was the question of acceptance. Many Americans would simply not be welcoming to natural hair in the White House. After all, in 2016 a federal court essentially ruled that approximating white people's hair makes one more qualified for jobs. The message that straight hair makes one " professional " and " appropriate " is constantly sent to black women and girls.

What would have happened if Michelle Obama had decided to wear an "ethnic" style? Americans did not find out. Mainstream standards are too rigid to be tested by a woman whose job is to be accepted as a representative of US womanhood.

And, make no mistake, representing American womanhood meant that she was held to standards that created a no-win situation. Some feminist critics insisted that focusing on Mrs. Obama's beauty and fashion choices was trivial, but this was easy to say because she made the "right" choices.

If Michelle Obama had worn dreadlocks or even a modest afro, her hair would have likely suddenly ceased to be a trivial topic among these purportedly progressive critics. I dare say it may have become a national security concern, because when black women don't seem to be trying to meet mainstream standards of beauty, they are sometimes assumed to be resisting "the American way."

In other words, it would have somehow confirmed the fears that cartoonist Barry Blitt caricatured for the cover of The New Yorker in July 2008, which showed Mrs. Obama with an afro and wearing combat gear, fist-bumping her husband beneath a portrait of Osama bin Laden.

Even while encouraging non-black women to identify with her, Michelle Obama's public persona also accounted for the messages black women received. Though she did not have dreadlocks or wear her hair in twists or braids, there was always the possibility that her hair was "natural," or free of chemical straightening -- known as a relaxer.

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By straightening her hair while occupying the White House, but also leaving open the possibility that it was natural, Mrs. Obama affirmed both black women who wear their hair straight and those who do not.

Since the "black is beautiful" movement of the 1960s, natural hair has been associated with self-love and self-esteem. Even while complying with what most Americans (and American courts) consider "professional" and "appropriate," Mrs. Obama avoided tampering with the idea that natural hair, for many black women, is the more loving choice.

As FLOTUS, Mrs. Obama's public persona demonstrated awareness that she was not free to go natural (conspicuously) but also that she was not willing to capitulate completely. The particular secret she kept created more flexibility for other black women, not less.

This is important because a prominent African-American woman's choices are so easily used against ordinary black women in their everyday lives. By keeping space open for black women, Michelle Obama's public persona demonstrated that she found them relevant. Black women mattered to this first lady.

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Now that she's out of the White House, she can fully embrace her status as an extraordinary woman. As she continues to promote public health, for example, she is no longer Mom-in-Chief doing so, but a former medical center executive.