Bestselling self-help author Marianne Williamson, who brought quirky spiritualism to the 2020 presidential race, has announced she’s running for the White House again, becoming the first major Democrat to challenge Joe Biden for his party’s nomination in 2024.

Williamson, 70, pulled out of the 2020 presidential election in early January of that year, after failing to gain much traction with primary voters. She then endorsed Bernie Sanders for the Democratic nomination and he ended up coming in second to Biden, who had been trailing him badly but surged ahead after a crucial win in South Carolina.

But she has now signaled she will soon head to key early primary voting states New Hampshire and South Carolina and will visit the site of the recent toxic chemical train spill that has caused an environmental crisis in East Palestine, Ohio.

Williamson is formally kicking off her campaign with an event in Washington DC, on Saturday. Without mentioning former US president Donald Trump, she noted in a weekend Facebook post that his unconventional White House win in 2016 makes it “odd for anyone to think they can know who can win the presidency”.

“I’m not putting myself through this again just to add to the conversation,” Williamson wrote. “I’m running for president to help bring an aberrational chapter of our history to a close, and to help bring forth a new beginning.”

Williamson running against a sitting president from her own party would be the longest of long shots in any circumstances.

But that’s especially true this cycle, as the Democratic establishment – and even potential presidential hopefuls who could have competed with Biden from the left or middle – has closed ranks with remarkable uniformity behind the president.

Williamson declared: “I feel my 40 years being up close and personal with the trauma of so many thousands of individuals gives me a unique perspective on what is needed to help repair America. We need a politics that treats not just symptoms, but cause. That does not base itself on the crass imperatives of endless corporate profit, but on the eternal imperatives of our principles and values.”

She is a spiritual adviser to Oprah Winfrey.

One of her signature proposals was a plan to create a US Department of Peace. She also advocated that the federal government pay massive financial reparations to Black Americans as atonement for centuries of slavery and discrimination.