Donald Trump’s niece Mary Trump called on Wednesday for the president to resign and said her uncle was dangerous for America.

Trump, whose bombshell book about the family was published on Tuesday and trailed in the Guardian and other outlets last week, told ABC that the US is “on a precipice” with the November election coming up.

“He is utterly incapable of leading this country and it’s dangerous to allow him to do so,” Trump told ABC’s George Stephanopoulos on Wednesday morning, in her first interview since a court on Monday lifted a restraining order against her brought by Donald Trump’s brother Robert to try to prevent her speaking out.

The family’s attempt to block her book also failed. Trump is the daughter of Donald Trump’s late elder brother, Fred Jr.

Stephanopoulos asked Mary Trump, if she was in the Oval Office now, what she would say to the president.

“Resign,” she said.

Asked why she thought the president was incapable of holding the office, she said: “Based on what I have seen my entire adult life.”

She added: “This country is on a precipice and we have a decision to make about who we want to be and where we want to go as a country. It’s hard for me to process just how many awful things are going on simultaneously on a daily basis” out of the White House.

Donald Trump’s extraordinary character and outrageous behavior “threaten the world’s health, economic security and social fabric” and were shaped by his “high-functioning sociopath” father during childhood, the book says.

Mary Trump has described her grandfather, Fred Trump, Donald’s father, as a sociopath who shaped the emotional pattern of those around him.

“He [Fred] had no empathy, he was incredibly driven in a way that turned other people, including his children and his wife, into pawns to be used for his own ends.

“If someone could be of use to him he would use them, if they were not of use he exiled them, in my father’s case [Fred Jr], tragically, he was not of use.”

Fred Jr had an alcohol dependency and died from related illness when Mary was a child.

She said she wrote the book not for her own therapeutic exercise, though it may be an extension of the family’s dysfunction, she told ABC, with an ironic laugh.

But she said her motivation was her uncle, the president.

“I cannot let him destroy my country. There are so many parallels between the circumstances in which my family operated and in which this country is now operating – focusing on the wrong things, elevating the wrong people,” she said.

She added that it was the result of “allowing someone to live their lives without accountability.

“If I can do anything to change the narrative, to reveal the truth I need to do it.”

The White House has called Trump’s book lies. Donald Trump was tweeting shortly after the first part of the ABC interview aired and touched on several topics but none of them on his niece’s book or Wednesday morning comments. More of the interview will be shown on Thursday morning.

Trump said Donald Trump’s father “restricted the range” of his son Donald’s emotions that were acceptable to the patriarch.

“Certain feelings were not allowed. Sadness, the impulse to be kind, generous,” she said, adding that Fred Trump thought such emotions were “superfluous, unmanly”.

Mary Trump also insisted that her assertion that Donald Trump paid someone to take his high school exams so he could qualify for the prestigious Wharton Business School, at the University of Pennsylvania, is true.

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