Bret Jaspers/KJZZ

Former second lady Jill Biden.

Jill Biden was in Phoenix on Friday as part of a book tour. Her memoir is well-timed for her return to the public eye as a high-profile surrogate for her husband, Democratic candidate for president Joe Biden.              

Before she read from her book, Biden talked about marrying Joe when she was 25.

“And he said, ‘Jill, your life will never change,’” she said, drawing laughter from the audience at the Arizona Biltmore. “Now, I don’t want to ruin the book for you, but he was ... he was wrong. My life changed and changed and changed again. And my life is still changing as we speak.”

Biden’s remarks were part of an annual luncheon put on by the Sandra Day O’Connor Institute. She didn’t take any questions from reporters.

The former second lady is probably more aware than anyone of what the public expects from the spouse of a presidential candidate.

According to political scientist Laurel Elder of Hartwick College, “they very much want the spouses to be out there, to be visible.”

Melania Trump, for example, saw lower approval ratings as a candidate spouse than her predecessors because she was not as much in the public eye.

“It wasn’t her husband, it wasn’t polarization. It was that she wasn’t out there. She wasn’t as visible and active as Americans have come to expect,” Elder said.

Elder is the co-author of "American Presidential Candidate Spouses: The Public’s Perspective" about public opinion of candidate spouses. She said Americans want to see the spouses but still within a traditional frame.

“They’re not even sure they want presidential candidate spouses to talk about their own accomplishments on the campaign trail,” she said. “They don’t like the idea of candidate spouses working, continuing their own careers while their spouse is in office.”

According to Elder, that attitude changes slightly when Americans are polled about a hypothetical male spouse. The data show people are slightly more comfortable with a candidate's husband having more autonomy.

Elder is curious to see if the traditional aspects of the spousal role frees up during the 2020 cycle, making it more acceptable for the candidate’s spouse to work, do policy work, or simply keep a lower profile. There will certainly be more candidate husbands making campaign stops over the next year than people have seen in the past.

“It’s a really interesting window into gender politics and gender relations in American society, in part because our expectations for spouses have been so traditional,” she said. “They’ve lagged behind what is going on in society overall.”