As a blast of arctic cold, and a paroxysm of hysteria over Michael Wolff’s new book, fell over Washington on Thursday, First Daughter and senior White House aide, Ivanka Trump, and her colleagues in the Office of Legislative Affairs, left the West Wing and headed over to Capitol Hill. A White House official explained that they checked in with members of Congress regarding an agenda for working families that the administration is hoping to advance this year. Later that evening, she and her husband, senior White House adviser Jared Kushner, hosted a belated holiday party that they had planned weeks ago at the Trump Hotel, with the likes of Gary Cohn, Dina Powell, H.R. McMaster, and Sarah Huckabee Sanders toasting in a private room.

On its face, it may not have seemed like an evening worthy of celebration. Wolff’s book, after all, purported to quote senior staffers questioning President Donald Trump’s ability to handle the job—to grasp foreign policy, to take in lessons about constitutional amendments, and even to read without visual aids. Relying heavily on quotes and stories from former White House strategist Steve Bannon, who feuded with the Trump-Kushners for months in the West Wing and in the months since he got fired in August, Fire and Fury takes constant aim at the second First Couple. Wolff said Bannon described Ivanka as “dumb as a brick,” and says that Trump placed Middle East peace within Kushner’s broad White House portfolio because his family, longtime Israel supporters, “knew all the crooks” in the country. “The daughter will bring down the father,” he reportedly says of Ivanka, at another point. Most notably, the book quotes Bannon suggesting that the Trump Tower meeting between Kushner, Don Jr., and a Russian lawyer offering dirt on Hillary Clinton was “treasonous.” Bannon added that he believes that Special Counsel Robert Mueller will end up digging up dirt on money laundering. “The Kushner shit is greasy. They’re going to go right through that.”

Bannon’s remarks prompted a swift response from the White House. On Wednesday, White House aides huddled with the president, who’d already polled people close to him about how to respond, to craft a statement torching his former strategist. “Steve Bannon has nothing to do with me or my Presidency,” the statement read. “When he was fired, he not only lost his job, he lost his mind.” By Thursday, Bannon was not only alienated from Trump; he was also cut off from other longtime supporters, Tina Nguyen reported. Rebekah Mercer, his primary financial backer, issued a rare public statement backing away from him; several candidates, who’d not long ago kissed Bannon’s ring, distanced themselves; and some staffers at Brietbart News wondered if Bannon could hold onto his position as chairman if he was at war with President Trump. According to my colleague Gabe Sherman, Bannon allies believe that the White House enlisted Kellyanne Conway to lobby Mercer, who has held conversations with Breitbart C.E.O. Larry Solov and Andrew Breitbart’s widow about removing Bannon from the company.

It would be understandable had the combination of a public-relations fiasco and a rapt audience, thanks partly to the “bomb cyclone” that snowed in the Northeast Corridor, dampened the enthusiasms of the Trump-Kushners. But, according to people familiar with their thinking, the revelations about Bannon validated Kushner and Ivanka, who had, for months, seen Trump’s former adviser as enemy No.1—someone who constantly undermined them and leaked negative information about them to the press. Now, the duo seemed to feel that Bannon had exposed his duplicitous nature to their president and their former colleagues. “They’re ecstatic,” one person familiar with their thinking told me. “They’re just so glad that everything is finally out there.”