Politics Trump Was 'Done' with Republican Party Until Officials Said They'd Ruin a $100M Political Tool: Book Jonathan Karl's new book, Betrayal: The Final Act of the Trump Show, details the former president's threats to leave his party — which Trump disputes, calling the whole thing "fake news" By Aaron Parsley Aaron Parsley Aaron Parsley has been a part of PEOPLE's digital team for more than 15 years. People Editorial Guidelines Published on November 8, 2021 02:00 PM Share Tweet Pin Email Donald Trump and Ronna McDaniel. Photo: Chip Somodevilla/Getty; Nick Hagen for The Washington Post via Getty With only hours left in his presidency in late January, a defeated Donald Trump was so furious at fellow Republicans for not sufficiently supporting his attempts to overturn the 2020 election results that he wanted to leave the political party to start his own, according to a new book, which he disputes. In Betrayal: The Final Act of the Trump Show (published next week), author and ABC News Chief Washington Correspondent Jonathan Karl writes about a conversation between the outgoing president and Republican National Committee Chairwoman Ronna McDaniel, which took place on over the phone shortly after Trump boarded Air Force One for the last time. On Jan. 20, Trump, 75, skipped the inauguration of Joe Biden at the U.S. Capitol, attending instead a small send-off with family and supporters at Joint Base Andrews in Prince George's County, Maryland. From there, he took the presidential plane to his private club in West Palm Beach, Florida. Karl writes that shortly after Trump boarded Air Force One, McDaniel, who was unable to attend his goodbye ceremony due to recent ankle surgery, had a "very unpleasant conversation" on the phone in which he said he was "done" with Republicans. Former Attorney General William Barr Calls Donald Trump's Election Lies 'Bull----' In New Book "Donald Trump was in no mood for small talk or nostalgic goodbyes. He got right to the point," Karl writes. "He told her he was leaving the Republican Party and would be creating his own political party." Donald Trump Jr. was also on the phone, according to Karl, attributing his details to sources with direct knowledge of the events. "You cannot do that," McDaniel said, according to Karl's book. "If you do, we will lose forever." To that, Trump replied, "Exactly. You lose forever without me. I don't care." (Spokespeople for Trump and the GOP did not immediately respond to PEOPLE's requests for comment. Karl writes that Trump denied this version of events in an interview with him.) From left: Melania Trump and Donald Trump exit Air Force One at the Palm Beach International Airport on the way to their Mar-a-Lago Club not long before Joe Biden is inaugurated as president on Jan. 20. Noam Galai/Getty According to Karl, Trump spoke in his call with McDaniel as if he wanted to punish Republicans for betraying him by not fighting hard enough to support his false assertions that the election was stolen from him. Those same lies fueled both a deadly riot by his supporters at the Capitol and historic impeachment charges against him. "This is what Republicans deserve for not sticking up for me," he told the RNC chairwoman, Karl writes. The Legal Problems Trump Faces Out of Office - from Capitol Attack to Accusations of Fraud to Defamation McDaniel was also forceful in arguing with Trump, according to Karl's book. "This isn't what the people who depended on you deserve, the people who believe in you," she said. "You'll ruin your legacy. You'll be done." Though Trump was "very adamant," McDaniel and other top Republican Party members eventually convinced Trump and his closest advisers to back down from the threat to leave the party. "We told them there were a lot of things they still depended on the RNC for and that if this were to move forward, all of it would go away," a party official told Karl. In particular, Karl writes, the RNC said it would stop paying legal bills for post-election court challenges and would ruin what Karl describes as Trump's "most valuable political asset": a list of 40 million emails belonging to Trump supporters. Donald Trump. Steven Ferdman/WireImage Mike Pence Calls Trump's Push to Overturn the Election 'Un-American' but Praises Him as a Disruptor That list of emails, according to Karl's book, is worth an estimated $100 million because the Trump campaign could lease it to other Republicans for a price. But the coveted list is owned by both the RNC and the Trump campaign, Karl reports. The RNC told the former president that if he left the party, they would give it out for free, making his campaign unable to charge for access to supporters' emails. Karl writes that Trump, who later said he would remain a member of the Republican Party, denied in an interview that he ever planned to leave or start his own political party — though such a possibility was previously reported in The Wall Street Journal. Trump also dismissed accounts of a standoff between him and the RNC as "fake news." McDaniel likewise pushed back on Karl's account, telling ABC News: "This is false, I have never threatened President Trump with anything. 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."