Trump threatened to start his own political party in a tense clash with the RNC on his last day in office, book says

• On his last day in office, Trump threatened the RNC that he'd start his own party, per a forthcoming book.
• Trump felt betrayed and abandoned by the GOP, ABC News correspondent Jonathan Karl reports.

Former President Donald Trump threatened to start his own political party in a tense standoff with Republican National Committee officials on his last day in office, according to a forthcoming book by ABC News correspondent Jonathan Karl, titled "Betrayal: The Final Act of the Trump Show."

On January 20, Trump was bitter over his election loss and what he saw as insufficient loyalty from the rest of the GOP after the January 6 insurrection. Ten House Republicans voted to impeach him for inciting the Capitol riot.

So, on his way out the door, the former president had what Karl described as an "unpleasant" conversation with RNC Chairwoman Ronna McDaniel.

"I'm done," Trump said to McDaniel, according to the book. "I'm starting my own party."

"You cannot do that," McDaniel replied to Trump. "If you do, we will lose forever."

"Exactly. You lose forever without me," Trump shot back. "I don't care."

Trump told McDaniel that starting his own party was "what Republicans deserve for not sticking up for me," Karl wrote.

"This isn't what the people who depended on you deserve, the people who believed in you," McDaniel pleaded with Trump, according to the book. "You'll ruin your legacy. You'll be done."

Trump's threat to break off and start his own party comes amid tension between the Trump and RNC camps before and after the election. They include a reported episode where Trump's son-in-law Jared Kushner told McDaniel he "didn't give a fuck about the future of the Republican party," and blowups between the RNC's lawyers and Trump's attorney Rudy Giuliani, who were both litigating Trump's challenges to the 2020 election results.

But the RNC had two important weapons in their arsenal, and decided to "play hardball," Karl wrote.

If Trump broke away from the GOP, McDaniel said, the committee wouldn't keep footing the bill for the remaining legal fees accrued from Trump's challenges to the 2020 election.

And, more importantly, the RNC could make the enviable email contact list of Trump donors and supporters, with an estimated value of $100 million, virtually worthless to Trump overnight, Karl reported.

After the RNC outlined the stakes of such a move, Trump quickly backed down from his threats, Karl wrote.

McDaniel denied threatening to take away Trump's access to the email list, but did not deny that she had a conversation with him about starting his own party.

"This is false, I have never threatened President Trump with anything," McDaniel told ABC. "He and I have a great relationship. We have worked tirelessly together to elect Republicans up and down the ballot, and will continue to do so."

In an interview with Karl for the book, Trump called the notion that he threatened to start his own party "bullshit," and issued a further denial to ABC News' report on the book.

"ABC Non News and 3rd rate reporter Jonathan Karl have been writing fake news about me from the beginning of my political career," Trump said in response to the report. "Just look at what has now been revealed about the Russia, Russia, Russia hoax. It was a made up and totally fabricated scam and the lamestream media knew it. It just never ends!"

Karl's book, "Betrayal: The Final Act of the Trump Show," will be published by Penguin Random House and is due for release on November 16.