CNN anchor Jake Tapper faced strong criticism during a call on C-SPAN about his new book detailing former President Joe Biden’s cognitive decline. The caller accused Tapper of showing bias towards current President Donald Trump and providing unfair coverage.

Tapper appeared on Tuesday’s edition of “Washington Journal” to discuss “Original Sin: President Biden’s Decline, Its Cover-Up, and His Disastrous Choice to Run Again,” the bestselling book he co-wrote with Axios reporter Alex Thompson.

During the C-SPAN call-in show, Tapper was confronted by Sarah, a caller from Virginia who voiced frustration over what she saw as one-sided reporting.

“I watch you on CNN,” she began. “But right now, I really don’t like you. I think you’re doing a disservice to Joe and also to the American people.”

Sarah questioned why Tapper hasn’t applied the same level of scrutiny to Trump’s behavior and fitness for office.

“When are you going to examine what is going on with Trump? Joe Biden conducted himself for four years taking care of the United States. He took meetings. He went overseas. He negotiated with other leaders,” she said.

“This president has been pure chaos, which indicates to me that there is something wrong with him. We will never get a straight answer on his medical examinations, what medication he is on, and yet you have gone after Joe Biden with a vengeance that… I’m very disappointed in you.”

The caller said she used to enjoy Tapper’s show “The Lead,” but that his recent focus had changed her view.

“And I think right now you ought to start writing another book examining Trump and how erratic [he is] and what he is doing, calling out the National Guard, the Marines, and everybody,” she added.

“When has a president ever done that? It’s pure erratic!”

Tapper, who has acknowledged that he failed to adequately devote scrutiny to the question of Biden’s fitness while he was president despite apparent signs of his decline, responded calmly, defending his coverage and encouraging viewers to tune into his daily CNN broadcast.

“Sarah, as you know from watching my show on CNN, we cover President Trump every day for two hours — every day from 5 to 7 Eastern — and we cover all the things you talk about, in terms of the current president’s behavior,” he said.

He pointed to past instances where Trump confused public figures, saying, “We have covered the times that he has confused Nancy Pelosi with Nikki Haley.”

“I think some of the questions about President Trump’s behavior have more to do with personality than with cognitive decline,” Tapper added.

“Whatever lessons we’ve learned from covering President Biden, we would apply to any politician,” he continued.

“So I’m sorry if I’m disappointing you by covering President Biden. But journalists, we are supposed to cover stories that we think the American people have a right to know, that we think will enhance their understanding of how the country is run.”

Tapper closed the exchange by reaffirming his belief in the book. “We are proud of this book,” he said, adding that CNN would continue to cover current events in the days ahead.

“Washington Journal” is a live, daily call-in program on C-SPAN that gives viewers the chance to directly engage with elected officials, journalists, policy experts and other public figures about current political and policy issues.

It typically airs every morning, seven days a week, and covers a wide range of topics including legislation, national events, and public affairs.

The show is known for its unfiltered, interactive format whereby viewers call in and ask questions or share opinions live on-air — often divided by political affiliation.

“Everyone knows that C-SPAN callers are cranky and that’s part of the charm of the show,” a media source told The Post.

Unlike many news programs, “Washington Journal” maintains a nonpartisan approach, providing a neutral platform for discussion and civic engagement.

The book alleges that White House aides worked to conceal the then-president’s deteriorating mental and physical condition during his time in office.

Since its release, Tapper has made headlines by calling the alleged cover-up “worse than Watergate” and describing Hunter Biden as acting like the “chief of staff of the family.” He has also stated that “conservative media was right” to raise concerns about Biden’s age.

House Republicans have already cited the book to justify an expanded investigation into what they claim is a cover-up of Biden’s health.

A representative for Tapper declined to comment when reached by The Post.