Actress, #MeToo activist and resistance icon Alyssa Milano shocked fans by announcing last Tuesday that she would be attending a fundraiser for New Age guru and Democratic presidential hopeful Marianne Williamson.

Twitter exploded in condemnation. Many commentators noted Williamson’s opposition to vaccine mandates and other unusual beliefs.

"I know. I know,” Milano replied. “But she’s the only candidate talking about the collective, soulful ache of the nation & I think that’s an important discussion to have."

OK, let’s have that discussion: What does Marianne Williamson believe, and what impact might her beliefs have on her fitness to be president?

Let’s start with the basics of Williamson’s ideology, which was first formed on the Upper West Side of Manhattan, where she discovered the book “A Course in Miracles,” itself a relic of the neighborhood’s 1960s “mystical heyday,” according to The New York Times. Williamson burst onto the national scene in 1992 when talk show host Oprah Winfrey championed her first book, “Return to Love: Reflections on the Principles of A Course in Miracles.” Oprah’s support turned the book into a smash hit. It sold over a million copies in its first year in print and spent 39 weeks on The New York Times bestseller list, making Williamson the most prominent interpreter of “A Course in Miracles.”

“A Course in Miracles” is an authentic New York phenomenon, though hometown boosters should be warned that it isn’t anything to be particularly proud of. It is, however, a product of a mystical subway experience, crippling anxiety, psychotherapy, atheism, academia, Judaism and an explosively dysfunctional creative collaboration. Arguably, “A Course in Miracles” is the most quintessentially New York religion of all time.

Depending on who you believe, the author of “A Course in Miracles” is either Helen Schucman, a professor of psychology at Columbia University, Jesus, or - according to Williamson - some other divine authority. I vote Schucman.

Helen Schucman and her boss, Bill Thetford, had a relationship that could generously be described as tumultuous. The two were professors of psychology at Columbia University’s College of Physicians. Life in the department was characterized by “professional jealousy, fierce competition, and outright backbiting,” and the outspoken Schucman frequently clashed with the more reserved Thetford.

Eventually, in 1965, Bill gave a Helen pep talk about how there must be another way for them to work together, and according to the preface of “A Course in Miracles”, Helen really took Bill’s lecture to heart: She started experiencing visions and went on to write the text that became the Course, according to Ann Taves’ landmark history of the subject, contained in her 2016 book, "Revelatory Events."

Helen confided to Bill that she was receiving messages from a higher power. Instead of referring her for psychiatric help, as you might expect a clinical psychologist to do, Bill became “A Course in Miracles’” devoted midwife, soothing and encouraging the anxious Helen at every turn - in between blowout fights. Helen was ambivalent about the material that was coming out of her. She considered herself a militant atheist, yet here she was, apparently transcribing the thoughts of Jesus for posterity.

The initial goal of “A Course in Miracles” was repairing Helen and Bill’s tempestuous relationship. It didn’t work. “Jesus” spends a lot of time complaining in the meta-commentary that the two humans he has entrusted to bring his message of love and forgiveness to the world have not internalized a damn thing he’s trying to tell them.

It’s impossible to summarize “A Course in Miracles’” doctrine concisely because it’s not coherent. But let me give it my best shot: The external world isn’t real. All of our problems are illusions. You are the son of God, so am I, so is every other sentient being, so is Jesus, who is writing the book. There is no sin. Evil does not exist. Sickness is an illusion.

Interestingly, though it was written in the 1960s, the book was not a product of the counterculture. Schucman insisted that her disciples not display any trappings of hippiedom when they taught the Course.

Marianne Williamson, by contrast, was a full-blown flower child. By her own account in “A Return to Love,” she spent her youth bouncing between unfulfilling jobs and doomed love affairs, embracing left-wing politics but unable to escape her deep inner pain.

Williamson writes that she came across a multi-volume set of “A Course in Miracles” on a friend’s coffee table in New York in 1977. As a Jew, she found the Jesus language offputting. A year later, she returned to the text and was too depressed to notice the Jesus stuff. She never looked back.

According to Williamson, not only is the real world an illusion, everything is an illusion, except love. God is love. We only think that we are separate from each other and separate from God - in reality, we are all one. All of our problems, including sickness, are illusory. If we could just get beyond the illusion of sickness, we wouldn’t be sick.

If sickness is all in our mind and our minds can be changed by miracles, you might assume that miracles can cure disease. “Sometimes a miracle is a change in material conditions, such as physical healing,” Williamson writes in “A Return to Love.” "At other times, it is a psychological or emotional change.” This is the bait-and-switch at the heart of Williamson’s teachings. Maybe you’ll get well, or maybe you’ll feel better about being sick, but either way, she'll get your money.

Williamson began lecturing about “A Course in Miracles” to small groups in Los Angeles in 1983 and her following grew rapidly. A former cabaret singer, she brought the glamour and charisma that was lacking in the Course’s schlubby founders.

Many of Williamson’s early fans were gay men living with AIDS, and her theology seemed to promise the potential for miraculous healing. She even claimed that attending her spiritual support groups could prolong the lives of AIDS patients.

As a spiritual exercise, Williamson asked her clients to write letters to their disease expressing their feelings and to invent replies from the virus. She reproduces some of these dialogues in a bizarre section of “A Return to Love.”

Steve, a young man living with AIDS, thanks his virus for “making him a grown-up” and “giving him a reason to live.” Steve’s AIDS virus responds: “If I was, as they say, ‘out to get you,’ don’t you think you’d be dead by now? I’m not able to kill, harm, or make you sick. You give me the power you should give to God.”

When Carl begged to know why AIDS was killing him and his friends, Carl’s AIDS virus griped, “Right now, I feel like you only want to destroy me instead of dealing with whatever it is inside yourself that brought me here.”

The book came out in 1992, before medical science discovered the protease inhibitor drugs that made HIV a treatable disease. Yet, Williamson was encouraging her clients to love the virus that was killing them and to reflect on what they had done to make themselves sick.

Williamson’s co-founder of the AIDS charity known as the Los Angeles Center for Living, the late Louise Hay, was much more explicit in her claim that faith can cure disease. Hay claimed to have cured her own cervical cancer by alternative healing with no help from medical science.

“A Course in Miracles” is part of a much older American tradition known as New Thought. New Thought arose in the late 19th century as women rebelled against a male-dominated medical establishment that took it for granted that women were inherently sickly and feeble. Doctors subjected anxious and depressed women to ineffective and disempowering treatments, like extended bed rest, forced weight gain and tons of opiates. As a result, some women, including Mary Baker Eddy, the founder of Christian Science, turned away from medicine and sought spiritual solutions to their mental and physical woes.

The originators of the Course were familiar with Christian Science. Bill Thetford was raised in the church, and Helen Schucman wrote in her autobiography that her mother had sent her to a Christian Science weight-loss coach as a teenager. The Course even credits Mary Baker Eddy as an important, if “incomplete” insight into the nature of the fall of man.

“The definition of New Thought is the belief that the mind has power over matter, that ideas have actual material force,” said Dr. Beryl Satter, a professor of American history at Rutgers who studied New Thought as part of an inquiry into religions founded by women.

According to New Thought, meditatively affirming that you are strong and healthy actually makes you healthy. This belief in “mind over matter” can be applied to anything from making money to finding true love. The claim isn’t just that a positive outlook makes you a more energetic entrepreneur or a more attractive date. New Thought is selling a magical idea that what you ritualistically affirm in your mind becomes real because you thought about it.

This is the so-called “Law of Attraction,” a term coined by Helena Blavatsky in 1877, and still popular in New Age books today, such as “The Secret,” the mid-2000s self-help bestseller. Positive thoughts are said to attract positive outcomes, and vice versa.

In the 20th century, New Thought got redirected toward making money. “God’s Salesman” Norman Vincent Peale published “The Power of Positive Thinking” in 1952, and the book so impressed Fred and Mary Trump that the family drove from Queens to Manhattan to worship at Marble Collegiate Church, where Peale served as senior minister.

Throughout Trump’s life, his pathological self-confidence has wreaked havoc on others, from the employees of his failed casinos to the soybean farmers crushed by his frivolous trade war. Magical thinking used to be considered evidence of immaturity or mental instability, but Trump’s supporters revere him for it.

The idea that our thoughts determine our fortunes sounds empowering, but this kind of magical thinking also has very dark implications. “The delusional aspect of it is, if you could create your own reality, then if anything goes wrong, it’s of course your fault,” Satter observed. Or, in Trump’s case, nothing is ever his fault and all evidence that conflicts with his self-created reality is “fake news.”

At times, Williamson sounds very victim-blamey. She claims that over-identification with the physical body at the expense of the spirit places a “stress on the body that the body was not meant to carry - and that’s where sickness comes from.”

When asked whether people get cancer because of bad thoughts, Williamson is quick to say that it’s not necessarily because of their own bad thoughts. Maybe a child got cancer because of someone else’s bad thoughts, she suggests, in “A Return to Love,” arguing that perhaps some evil chemical company executive’s bad thoughts led him to poison the water supply. But that argument conflicts with her theology’s core contention: If the child’s cancer is real (and not just an illusion) and the poisoned water is the real cause, then her claim that only love is real can’t be true. Never mind that it was the chemical executive’s actions that caused the pollution, not his thoughts. Williamson claims that “disease is loveless thinking materialized,” noting that lovelessness can be collective, like racism, which does indeed harm people’s health and shorten their lives. But this doesn’t explain how children are born with diseases that have no environmental or social cause, such as cystic fibrosis.

Marianne Williamson has made her fortune selling snake oil. In that, she has something in common with another candidate whose fortune started in New York City: President Donald Trump. And, like many of Trump’s assertions, her core ideas collapse under the slightest scrutiny. We’ve already seen in Trump the damage that a president can do through superstition and willful ignorance of science. “The collective, soulful ache of the nation” may be real, but Williamson’s cure isn’t.