Former US representative Liz Cheney has said her memoir coming out this autumn will detail her estrangement from former president Donald Trump and the Republican Party.
In Oath And Honor, she will write about her feelings in the aftermath of the January 6 siege of the US Capitol.
“The last two years have shown us once again that our constitutional republic is not self-sustaining,” Ms Cheney said in a statement released on Tuesday by Little, Brown and Company, which will publish her book on November 14.
“It survives only because of the courage and honour of individual Americans.
“When history looks back on this time, each elected official will have to answer the questions: Did we do our duty? Were we faithful to our oath of office?” Ms Cheney said.
Ms Cheney, daughter of former vice president Dick Cheney, had been a leading Republican voice for years but she parted with many of her colleagues over Mr Trump’s false claims of voting fraud and her position as vice chair of the Congressional committee that looked into the insurrection on January 6, 2021.
Ms Cheney has said she wants to ensure that Mr Trump, who has announced his candidacy for 2024, will never be president again.
Once a dominant presence in Wyoming politics, she was defeated in the Republican primary last summer by Harriet Hageman, who had been endorsed by Mr Trump.