In an extended conversation with NPR's Rachel Martin, Mary Trump said on Wednesday that her grandfather and family patriarch Fred Trump rewarded ruthlessness and dismissed any interests outside of the family real estate business, contributing to what she now views as an unfitness on President Trump's part to hold the office of the White House.
"It's kind of ironic in the sense that the traits my grandfather came to value in Donald were the traits that were a result of my grandfather's maltreatment of Donald," she said. "The bullying, the tendency not to care about other people's feelings, the willingness to cheat, lie to get what he wanted. And eventually ... my grandfather started to see a kindred spirit. Somebody who could advance his agenda."
Mary Trump, the president's only niece, describes an abusive and neglectful upbringing suffered by her father and uncles at the hand of Fred Trump, and said she will be supporting her uncle's rival, Joe Biden, in the 2020 election.
A trained psychologist living in New York, she was promoting her highly anticipated new book, Too Much and Never Enough: How My Family Created the World's Most Dangerous Man.
In the book, Mary Trump describes how her grandfather's relentless business ambition was passed down to Donald Trump.
"Honest work was never demanded of him, and no matter how badly he failed, he was rewarded in ways that are almost unfathomable. He continues to be protected from his own disasters in the White House," she writes in the tell-all.
"But now the stakes are far higher than they've ever been before; they are literally life and death. Unlike any previous time in his life, Donald's failings cannot be hidden or ignored because they threaten us all."
The White House has repeatedly dismissed the book as a money grab by the president's niece.
"The president describes the relationship he had with his father as warm and said his father was very good to him," White House spokeswoman Sarah Matthews said earlier this month.
"He said his father was loving and not at all hard on him as a child. Also, the absurd SAT allegation is completely false," Matthews said, referring to a claim in the book that the president cheated on the SAT by paying someone else to take the exam on his behalf.
The book, which was released Tuesday, is the second high-profile expose of the president this summer. In June, former national security adviser John Bolton won a legal battle to publish a review of his time at the president's right hand.
Robert Trump, the president's younger brother, sought to have a court block Mary Trump's book release and her promotion of it. A New York judge on Monday freed Mary Trump from an existing gag order restricting her from discussing the book. A separate and earlier court ruling had already allowed the publishing house Simon & Schuster to move forward with producing the account.
Mary Trump said that while she is not afraid to speak freely about her family history, she felt there were risks associated with talking about the president unfavorably.
"Realistically speaking, Donald has a position with which comes an enormous amount of power," she said in the Wednesday interview. "He has a following which has proven to be fairly fanatical. And from what I've seen, anybody who comes forward to speak truth to power or fulfill their obligations to uphold and defend the Constitution, if that clashes with Donald's agenda, they do not fare well."
"It's a very divisive world we're living in at the moment. And I understand that what I'm doing will be misinterpreted — sometimes willfully misinterpreted. And I just need to be careful."
Mary Trump also offered her opinion of the president's mental fitness.
"If you're in a room with him for two minutes and you're paying attention, you know that he's not doing well," she alleged. "Psychologically, he's absolutely unfit. Emotionally, psychologically, he is absolutely unfit."
Mary Trump did not speak in an official capacity as a psychologist. Mental health professionals typically refrain from diagnosing public figures they have not examined.
Asked whether she would be backing her uncle in the upcoming Nov. 3 general election, Mary Trump said she would support former Vice President Joe Biden.
