Washington (AFP) - Marianne Williamson was largely a political unknown until this week's Democratic debates.

But the author of books on spirituality has intrigued Americans with her performance and a simple vow to defeat President Donald Trump -- "love will win."

Speaking in a hoarse, throaty voice, the 66-year-old Williamson addressed the Republican president directly on Thursday night.

"So, Mr. President, if you're listening, I want you to hear me, please. You've harnessed fear for political purposes and only love can cast that out," she said.

"I'm going to harness love for political purposes. I will meet you on that field, and sir, love will win."

With that mini-speech toward the end of the 10-person debate -- the second night for the big Democratic field seeking to unseat Trump in 2020 -- Williamson made a name for herself.

Even though she got only five minutes of debate airtime, she owned Twitter for a while, became the most looked-up candidate on Google and got the US media talking about her.

Not bad for a presidential hopeful who had been running at zero percent in the polls.

Love, the driving force of her campaign, is also the mantra of her professional career.

Williamson's first book, "A Return to Love," which came out in 1992, was endorsed by talk-show queen Oprah Winfrey. 

She quickly became a regular on Winfrey's program, and has published 12 more books.

Williamson's story began in Houston, Texas, where she was born on July 8, 1952, the daughter of an immigration lawyer.

In her 20s, she began a quest for "spiritual understanding," as she writes on her website, and discovered a self-help program of spiritual transformation -- "A Course in Miracles," by Helen Schucman -- that she says changed her life. She now teaches according to its principles.  

In Los Angeles during the 1980s, with the AIDS epidemic ravaging affected communities, she established Project Angel Food to distribute food to some of the disease's most vulnerable victims.

She was briefly roommates with Laura Dern -- now a two-time Oscar nominee and star of popular HBO series "Big Little Lies" -- who was 17 at the time. They assembled meals for Project Angel Food from their apartment, according to The New York Times.

Williamson got an early celebrity endorsement in 2014 during her first political run, as an independent seeking a congressional seat from California, when singer Alanis Morissette, who had attended a Williamson seminar, wrote and sang "Today" for  her. 

Williamson finished fourth in that race. 

Since entering the US presidential campaign late in January, Williamson has been trying to shed her image as "Oprah Winfrey's guru" or as a "spiritual guru."

Her platform? Like most of her Democratic rivals, she leans to the left, calling for universal health care, an increase in the minimum wage and a "Green New Deal" to dramatically escalate the fight against climate change.

"We don't have a health care system in the United States, we have a sickness care system in the United States," she said during Thursday's debate, alluding to the thousands of Americans who die yearly of opioid abuse.

And in a country still profoundly scarred by a long history of slavery, Williamson has promised to pay reparations to black Americans totaling $200-500 billion over 20 years.

A serious candidate?

The Californian has said she decided to run because "experienced politicians have led us" to a place where climate change could mean "the survivability of the human race will be in question."

But some of her remarks in the debate left listeners shaking their heads.

Asked what her first act would be if elected, she said she would call New Zealand Prime Minister Jacinda Ardern and take her to task for saying she wanted to make her country "the best place in the world to be a child."  

"I would tell her, 'Girlfriend, you are so on,'" Williamson said. "The United States of America is going to be the best place in the world for a child to grow up."

Williamson has a 29-year-old daughter, India. 

If some of Williamson's debate comments raised eyebrows, some of her tweets have been even more perplexing. 

"If you want a simple explanation for what's happening in America, watch AVATAR again," she tweeted in 2017, referring to the science-fiction film about humans callously colonizing a lush moon inhabited by a gentle tribe of tall blue creatures.

But being the object of mockery may not trouble Williamson. 

She approvingly retweeted a comment from American commentator and journalist Quinta Jurecic that the candidate hopes will prove prophetic: 

"The more we joke about Marianne Williamson the more certain I am that she is going to be the next president of the United States."