After being sidelined by kidney surgery last month, first lady Melania Trump has been slowly returning to the public spotlight.

And Americans like her, for the most part. A recent CNN poll showed an upswing in support. As of May 2018, 57 percent of Americans said they had a favorable impression of her, up from 36 percent in January 2017.

This makes Melania Trump much more popular than her husband. And it’s a dramatic improvement from the 2016 campaign, when she had the dubious distinction of being the least popular candidate spouse of modern times.

But Melania Trump’s approval ratings are still lower than the remarkable levels of popularity enjoyed by her predecessors, Michelle Obama and Laura Bush, who maintained favorable ratings in the high 60s.

Our recently published book “American Presidential Candidate Spouses: The Public’s Perspective” looks into the recent rise in Melania Trump’s approval – and why she is unlikely ever to be as popular as Michelle Obama.

So why has Melania’s popularity risen?

1. Melania is a traditional first lady

The first explanation lies in Melania Trump’s stated desire to be a traditional first lady. Survey data reveal that Americans continue to prefer such a first lady — one who supports her husband, embraces her role as a mother and does not try to influence major policy initiatives.

Melania Trump has met many of these traditional expectations. She has made it clear she has no desire to advise her husband on politics. She has been fashionable and flawless in carrying out many of the ceremonial roles of the first lady — from greeting foreign dignitaries to hosting the Easter Egg Roll. That approach has won her support.

2. Incumbents have an advantage

A second factor behind Melania Trump’s rise in the polls comes from the advantage of being the incumbent. Much as elected officials benefit from being seen doing the job, sitting first ladies benefit from the visibility and perquisites of the office. All that boosts popularity.

However, that’s only if first ladies behave in a traditional manner. Barbara Bush, already very popular when she campaigned for her husband in 1988, grew even more popular over the next four years. Hillary Clinton, by contrast, was viewed less favorably in 1996 than in 1992.

By removing herself from political influence, underscoring that her priority is caring for her son and signaling that she wants to use the position of first lady to help children, Melania Trump has shown she fits the traditional mold and has reaped the benefits of incumbency.

3. The sympathy factor

A final factor behind the increase in Melania’s poll ratings may be sympathy. Survey data collected for our book indicate that some Americans hold a reserve of warmth for first ladies regardless of party, since they didn’t choose the spotlight but were placed in it by their husbands’ ambitions. Melania seems to benefit from the public understanding that she did not seek the spotlight that’s now on her.

Indeed, in the wake of news reports about President Trump’s alleged affairs with Stormy Daniels and Karen McDougal, Melania Trump’s popularity increased, suggesting that these scandals may cultivate even greater sympathy for her. Hillary Clinton’s favorable ratings rose similarly rose during her husband’s scandal with Monica Lewinsky as well. Melania has kept a steely silence on these issues, letting her spokeswoman comment that she is “focused on being a mom.”

But Melania Trump’s popularity still lags behind Michelle Obama’s

Given all this, why do her favorable ratings remain below Michelle Obama’s?

One hypothesis is that it’s because of Donald Trump’s historically low approval ratings. Views of presidential spouses are highly correlated with views of the president. Yet our analyses show that views toward Melania Trump were less influenced by views of her husband than is true for most presidential spouses.

Another hypothesis could be that American partisan polarization puts a ceiling on Melania Trump’s approval ratings. But it’s not the cause. Our research shows that views toward Melania are actually less polarized than views toward any presidential candidate spouse since 2000.

The reason: lack of visibility

Rather, the reason is Melania Trump’s near invisibility while campaigning – and her relatively low profile role as first lady. The polling data collected for our book reveal that close to 70 percent of Americans think it’s important that presidential candidate spouses are active, visible and campaign for their spouses. Melania Trump did not fulfill this expectation. While most presidential spouses headline hundreds of events, Melania Trump spoke at just a handful. She was completely absent from the campaign trail for months.

The public now expects first ladies to be active and visible, as well as traditional, a concept we call the “new traditionalism.” Here Melania Trump falls short. Since becoming first lady, she has given far fewer speeches than her predecessors. It took her until May of her second year in office to announce her Be Best Initiative. The evidence so far suggests she will not champion this initiative very actively or visibly.

In contrast, Michelle Obama perfectly embodied the new traditionalism. She gave up her own career, emphasized her role as “mom in chief” and refrained from political influence, while also being one of the most active first ladies both in appearing publicly and championing causes on behalf of children and families, among the most politically acceptable subjects for women. In turn she was beloved by most Americans.

In the end, Melania Trump’s low profile may enable future presidential spouses to opt out of the unpaid responsibilities expected of first ladies. But in the near future it will probably keep her from being as beloved as Michelle Obama.

Laurel Elder is professor of political science at Hartwick College.

Brian Frederick is associate professor and chair of political science at Bridgewater State University. 

Barbara Burrell is professor emerita of political science at Northern Illinois University.

Together they are the authors of “American Presidential Candidate Spouses: A Public’s Perspective” (Palgrave, 2018).