WASHINGTON – White House senior adviser Stephen Miller denounced writer Michael Wolff Sunday as "the garbage author of a garbage book."

Miller, on CNN's "State of the Union," disputed the broad outlines of Wolff's portrayal of President Donald Trump while deflecting a number of specific queries about episodes depicted in the book.

Miller was pressed in particular about the book's characterization of a June 2016 meeting with Kremlin-linked figures at Trump Tower in which the president's son-in-law, Jared Kushner, and son Donald Trump Jr. took part.

Wolff's book, "Fire and Fury: Inside the Trump White House," galvanized debate over Trump's fitness for office by asserting that the president's aides regard him as childlike, petulant and out of touch with reality. Trump has responded in recent days by denouncing Wolff, threatening legal action against him and tweeting a description of himself as a "very stable genius."

Asked about Trump's mental state, Miller said flatly that "no one questions the stability of the president." That echoed a statement from him in the early days of the administration, when Miller asserted in a television interview that Trump's executive powers "will not be questioned."

Jake Tapper, the "State of the Union" host, abruptly ended the interview after Miller repeatedly talked over his attempts to pose questions. Tapper called Miller "obsequious" and told him: "There's one viewer that you care about," referring to Trump.

Before that, though, Miller vigorously defended Trump's political acumen and grasp of voter sentiment.

"I saw a man who is a political genius," Miller said, adding that as a candidate, Trump had "tapped into something magical that is happening in the heart of this country."