Mary Trump: President Donald Trump is 'cruel and traitorous'

President Donald Trump's estranged niece, a clinical psychologist and author, says his baseless insistence that he won the presidential election is borne of his belief that he always deserves to win and "that it's OK to lie, cheat and steal" to do so.

Mary Trump, who wrote a book about the president and is penning another about America's history of trauma, said Trump has "nobody to blame but himself" for performing worse than other Republicans on the same ballots.

"He's spinning madly, he's desperate," she said, and if he "thinks he's going down, he's going to take the rest of us down with him."

Mary Trump is the daughter of Trump's elder brother, Fred Jr., who died after a struggle with alcoholism in 1981 at 42.