Among those already in Mr. Bannon’s sights: Speaker Paul D. Ryan; Senator Mitch McConnell, the majority leader; the president’s daughter Ivanka Trump and son-in-law, Jared Kushner; and Gary D. Cohn, the former president of Goldman Sachs who now directs the White House’s National Economic Council.

“The president was buoyed to election by capturing the hearts and minds of a populist, nationalist movement,” Alex Marlow, Breitbart’s editor in chief, said Friday evening. “A lot of it was anti-Wall Street, anti-corporatist, anti-establishment. And now we’re seeing that a lot of these guys remaining inside the White House are exactly the opposite of what we told you you were going to get.”