“Virtually every major move and decision the Reagans made during my time as White House Chief of Staff was cleared in advance with this woman in San Francisco who drew up horoscopes to make certain that the planets were in a favorable alignment for the enterprise,” writes Don Regan, President Reagan’s chief of staff, in his memoir, For the Record. Regan kept a color-coded calendar on his desk, with “good” days highlighted in green and “bad” days highlighted in red. Here’s the calendar for the first few months of 1986:

Jan 16–23 very bad

Jan 20 nothing outside the WH—possible attempt

Feb 20–26 be careful

March 7–14 bad period

March 10–14 no outside activity

March 16 very bad

March 21 no

March 27 no

March 12–19 no trips exposure

March 19–25 no public exposure

April 1 careful

April 11 careful

April 17 careful

April 21–28 stay home

Regan came to feel that this astrologer held disproportionate power over global politics, far more than many cabinet members vetted by Congress. “The president’s schedule is the single most potent tool in the White House,” Regan writes. Nancy Reagan spoke to this woman nearly every weekend and grew furious when the White House staff made last-minute adjustments to the schedule without leaving time for her astrologer’s approval.

The astrologer’s name was Joan Quigley. She was raised in a genteel San Francisco family, the closest California comes to old money. Her father owned a hotel and sent Joan and her sister, Ruth, to one of San Francisco’s toniest private schools. When Joan was fifteen, she sat in on one of her mother’s astrological consultations and was amazed by the certainty with which the astrologer could see the future and by the clean, almost mathematical quality of her methods. There was no communing with far-off spirits, no chanting, no tinctures, no grotesque velvet table covers.

By the time Quigley began working with the Reagans, she was in her fifties and had been working as an astrologer for decades, with high-profile clients such as the talk-show host Merv Griffin. She dressed like a card-carrying member of the Daughters of the American Revolution, her eyebrows always thinly plucked and her blonde hair secured in a bob.

Although Quigley had worked closely with the Reagans during the election, Nancy had stopped returning her calls during their first few months in the White House. But after the president was nearly killed by a shooter as he was exiting the Washington Hilton, Nancy reached out to Quigley again. “Could you have told about the assassination attempt?” she asked. Yes, Quigley assured her, she could have. She resumed her position in Nancy’s inner circle. She knew her involvement would need to be kept secret, as it was during the campaign. “I would be giving up my time and effort like all those who take part in any administration, sacrificing the rewards they commanded in the private sector in order to serve their country. I was aware, however, that unlike them I would not have the prestige they had while serving.” But Quigley worried about Reagan’s safety; his chart suggested that he was entering a risky period, and Quigley felt it was her duty as an American to protect her president from harm.

Millions of Americans read their horoscopes each month. Newspapers frame these monthly horoscopes as entertainment, and their devoted readers assure their skeptical friends that they skim them with breakfast “for fun,” too ashamed to admit to their instinct for magical thinking. People consult horoscopes for the same reason they consult advice columns—because everyone craves reassurance and because they address our ambitions and fantasies, the subjects that quietly consume us but that our daily lives often require us to ignore.

But unlike advice givers, there’s never been an astrologer who’s ascended to household name. The practice has too witchy an association. If Nancy Reagan had been open about her relationship with Quigley, if she had admitted that Quigley’s forecasts afforded her a greater sense of safety than any Secret Service report, the practice might have lost its taint, and perhaps Quigley would have become America’s first celebrity astrologer, remembered less for the accuracy of her predictions than for the way she made people feel.

*

Quigley waited and waited for a formal invitation to the White House. She was not invited to the party celebrating Reagan’s election in 1980 or his reelection in 1984—even though she considered herself crucial to both victories. Although she and Nancy spoke on the phone constantly, they’d met only once in person, and quickly, at an election event in San Francisco in 1976.

In April 1985, Quigley booked a trip to D.C. She didn’t tell any friends or family she’d be in town. Her trip had only one purpose: to take up Nancy on her open-ended invitation to tea at the White House. She happened to be in town on the night of a state dinner honoring the president of Algeria, and Nancy encouraged her to attend.

Quigley was careful not to wear any of the cocktail dresses she’d worn on The Merv Griffin Show. She went with an inconspicuous pale-blue gown. She was desperate to wear a new red dress, but she knew that red was Nancy’s color and didn’t want to upset her. Quigley hobnobbed with the editor of Newsweek, the actress Cheryl Ladd, and various journalists and political types. Quigley introduced herself as a writer from California and evaded further questions. She stepped out of the way anytime she saw the flash of a camera—for Nancy’s sake, she wanted no photographic evidence of her presence. “Nancy quite obviously did not want to make a point of my being there,” she later writes. She was seated at the same table as Vice President George H. W. Bush, whom she complimented for his debating skills. She ate seafood mousse and drank champagne.

The next day, she finally had her long-awaited tea at the White House. Nancy and Quigley gossiped about the previous night. They laughed about George Shultz, the secretary of state, who had forced Cheryl Ladd to dance with him. “He loves to dance with all the pretty young glamour girls,” Nancy said. They debated Bush’s chances at the presidency; Quigley believed he was fated to win, and Nancy believed he was too weak to lead. They talked about Nancy’s marriage, her horoscope, and her husband’s place in history. Quigley told her about the museums and galleries she’d visited in D.C.—it was important to her that Nancy see her as educated and cultured, not as some grungy outsider with a sixth sense. When they said goodbye, Quigley thought, “This woman could chew someone up and swallow and spit up the bones and never feel a thing.”

*

Quigley expected a thank-you. Nancy had promised as much—that one day, after they were out of office, Nancy would tell the world just how much Quigley had done for the Reagans and the country. Shortly after Don Regan published his memoir, in which he complained at length about the unchecked powers of an unnamed astrologer, someone within the administration leaked Quigley’s name to the press. Nancy was frantic to discredit the story. It was Ruth, Joan’s sister and roommate, who picked up Nancy’s call.

“This must never come out!” Nancy said.

“Not while you’re in office,” Ruth replied. “But what about after you are out of office?” She, too, hoped that her sister would receive her proper due.

“Never,” Nancy said.

In 1989, Nancy Reagan published her own memoir, My Turn, in which she addressed Don Regan’s allegations about her dependence on astrology. “Astrology was simply one of the ways I coped with the fear I felt after my husband almost died,” she writes. “My relationship with Joan began as a crutch, one of several ways I tried to alleviate my concern about Ronnie.”

Quigley was so offended by Nancy Reagan’s dismissive portrayal of her that in 1990, she wrote a memoir of her own, What Does Joan Say? The title is, purportedly, what the president would ask Nancy before scheduling an important event. In the book, Quigley describes how she assisted with important trade negotiations, assured the success of crucial public addresses, and helped keep the president safe. (“Ronald Reagan is the first president elected in a zero year to survive his terms of office since William Henry Harrison died after a month in office on April 4, 1841,” she writes.)

Quigley, who died in 2014, said she foresaw Nancy’s betrayal. “Struggle has been in my charts,” she once told a reporter. She knew she could “expect no gratitude” from the Reagans, and yet she said she did not foresee writing a memoir defending her place in history. Knowing in advance that the Reagans would hurt her made no difference. It hurt all the same.

Jessica Weisberg is an award-winning writer and producer. Her writing has appeared in The New Yorker, the New York Times, Harper’s, and The Atavist, among other publications, and been nominated for a National Magazine Award. She was a producer on the podcast Serial and runs the features unit at Vice News Tonight on HBO, for which she’s been nominated for an Emmy. She lives in Brooklyn.

Excerpted from Asking for a Friend: Three Centuries of Advice on Life, Love, Money, and Other Burning Questions from a Nation Obsessed, by Jessica Weisberg. Copyright © 2018. Available from Nation Books, an imprint of Perseus Books, LLC, a subsidiary of Hachette Book Group, Inc.