WASHINGTON — Former President Joe Biden’s longtime spokesman Andrew Bates grimly arrived at the Capitol Friday to be grilled by the House Oversight Committee about the alleged coverup of Biden’s cognitive decline.

Bates, 38, worked as a top spokesman for the Democratic leaders’s 2020 presidential campaign and followed him into the White House as a deputy press secretary.

The Oversight Committee asked Bates about the frequency of his interactions with Biden over his four years in the West Wing — after a different former spokesman, Ian Sams, testified in August that he spoke face-to-face with the then-president just two times in his own two-year stint.

“His meetings with President Biden were not frequent,” a source with direct knowledge of his interview told The Post.

“He would see President Biden in person a little over once a month, but this could be anything from travel, going with him to the Hill, or just seeing him in the hallway. He also stated that President Biden met with the press team a couple of times a year.”

Bates revealed in the sitdown that he interacted with more than 20 people about Biden’s physical and mental state to field questions from the press, according to the same source.

The ex-White House aide also maintained that the 46th president could have won re-election, that voters concerns’ about his age were unfounded, and that alarm over Biden’s debate performance in June 2024 before being forced out of the race were “overblown,” the source added.

Asked about the president’s incoherent response — “We finally beat Medicare” — to a question about the national debt, per the source, Bates also said he remained unbothered because he’d heard his boss say “we finally beat Big Pharma” before.

Bates was a divisive figure among Biden-era colleagues and the press — with fans viewing him as clever and effective and critics deeming him overly aggressive in dispensing spin.

“Bates being called to testify and be truthful is laughable to both journalists and his colleagues because he never operated with honesty,” a former Biden White House official said.

“Many of us watched him blatantly lie or twist the truth to ‘fix’ stories. In doing so, he’s destroyed his credibility… and for what?”

Oversight Chairman James Comer (R-Ky.) in an interview Friday on Fox News’ “Mornings with Maria” declared “there was clearly a cover-up of Joe Biden’s mental decline.”

“What we’re trying to get down to is the specific instances when Joe Biden’s signature was used on the autopen,” he added, referencing emails reported by The Post that raised questions about whether the 46th president was consulted before the mechanical device affixed his signature to pardons.

“The thousands of pardons that were signed with the autopen — as well as the legal documents like the executive orders that were signed with the autopen — these are all in question now,” Comer said.

An Oversight panel spokesperson accused Bates of being “part of the Biden cognitive decline cover-up” in a statement after the former White House aide’s opening remarks declared “it was universally understood that Joe Biden was in charge” throughout his term in office.

“He’s delusional,” added the rep for the GOP majority on the committee. “His so-called opening statement — leaked in the middle of his transcribed interview and not even read at the time it was leaked — peddled the same fantasy he’s been trying to sell the American people.”

In his opening statement to the committee, Bates said: “I was proud to support Joe Biden as President because we believe in the same values. In the White House, it was universally understood that Joe Biden was in charge. That is completely consistent with my personal experience with the President.”

Bates was known for forcefully — and effectively — pushing journalists at major news outlets such as the New York Times to give more favorable coverage to his boss. He also successfully pushed “Dark Brandon” memes on social media to blunt embarrassing “Let’s Go Brandon” heckling.

Last June, Bates led the charge in branding videos showing Biden, then 81, appearing to freeze up at events in Italy and Los Angeles as out-of-context “cheap fakes” — weeks before fellow Democrats revolted to force the incumbent to relinquish the party’s nomination due to similar debate-stage moments.

He also was key in pushing back on Biden’s attack on Trump’s supporters as “garbage” and was used as an “attack dog” in a number of instances, the ex-White House colleague recalled.

Then-press secretary Karine Jean-Pierre allegedly “used him to attack” journalists who buzzed about her use of a publicist for self-promotion — successfully keeping that relationship under wraps until the term ended.

“They used him so bad, so it’s not all his fault,” the former coworker said. “He was on X… before Biden dropped out saying it was never going to happen.”

A different ex-Biden aide, Jeremy Edwards, praised Bates as “a colleague who looked out for us — someone you knew would have your back — and who operated with integrity” and touted his role “fighting dangerous misinformation during the federal response to Hurricane Helene.”

Bates’ most controversial statements generally had a kernel of truth.

For example, in October 2020 he refuted The Post’s initial reporting on files from Hunter Biden’s abandoned laptop showing Joe Biden dined at a Georgetown restaurant in 2015 with Vadym Pozharskyi, an executive at Ukrainian gas firm Burisma Holdings, which was paying his son $1 million a year while the elder Biden led US policy toward Kyiv.

“We have reviewed Joe Biden’s official schedules from the time and no meeting, as alleged by the New York Post, ever took place,” Bates said at the time, as major news outlets relayed the refutation as a debunking and as Twitter and Facebook throttled circulation of the reporting.

After the electoral importance had passed, it became clear that the encounter did indeed occur — despite not being on Joe Biden’s official schedule — and also featured business executives from Russia and Kazakhstan who courted the then-second son.

Bates in his own remarks ripped the Oversight panel for “spending taxpayer dollars investigating Joe Biden — an honorable man under whom the economy performed far better than it is today — while turning a blind eye to corruption under Donald Trump.”

But he also revealed that he had spoken with Hunter Biden just 10 times while working as a spokesperson for his father, the source familiar with Friday’s interview noted.

“Andrew Bates never asked President Biden or Hunter Biden if the information on Hunter Biden’s laptop was true,” the source added, pointing out that the aide was also “in favor” of pardoning the president’s son.