The White House has attempted to dismiss President Biden's gaffes, miscues and mental acuity concerns as little more than the product of "cheap fakes" and misinformation, but one of Biden's current political rivals – who previously served alongside him – says unequivocally that the Biden seen during a disastrous national debate is "not the same man" he once knew.

Rep. Ronny Jackson, R-Texas, served as physician to the president during both the Obama and Trump administrations and previously worked in the White House Medical Unit during the George W. Bush administration. It was during his time spent serving under former President Obama that he was able to most closely observe Biden, then the vice president.

"I was in the White House when Joe Biden was VP, and the man we’ve seen since announcing his candidacy is not the same man who was VP for 8 years," Jackson said. 

Fox News Digital gathered various videos showing how Biden’s once-cogent speeches and energetic public appearances during his days as vice president have given way to a drastically different demeanor as president.

Thursday evening’s debate against Biden's likely general election foe, former President Trump, significantly elevated concerns about Biden’s age and mental acuity. 

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Joe Biden in 2024 debate

President Biden looks down as he participates in the first presidential debate of the 2024 elections with former President Trump at CNN's studios in Atlanta on June 27, 2024. (Photo by ANDREW CABALLERO-REYNOLDS/AFP via Getty Images)

The debate had a cascading effect within the media and some members of the Democratic Party, too, as even traditional left-wing allies slammed the president's performance as disastrous – with some calling on the president to step aside before the election. 

As legacy media outlets such as the New York Times and the Chicago Tribune call on Biden to map out an exit plan – with the Times describing Biden as a "shadow of a great public servant" – Biden allies such as Obama and first lady Jill Biden have reiterated their full-throated support for the 46th president’s re-election. 

Other Democratic allies floated as potential replacement presidential candidates, including California Gov. Gavin Newsom and Michigan Gov. Gretchen Whitmer, have also remained committed to their support of Biden's re-election efforts despite media calls for Biden to step aside. 

However, the Fox News Digital video compilation illustrates the differences in Biden that even some of his supporters are beginning to publicly acknowledge.

Rep. Ronny Jackson, Joe Biden

Texas GOP Rep. Ronny Jackson, a former White House physician, right, said special counsel Robert Hur's report "validates" what he and many Americans have known all along – that President Biden has "serious issues." (Getty Images)

"Mr. President, this honor is not only well beyond what I deserve, but it’s a reflection on the extent and generosity of your spirit.  I don’t deserve this, but I know it came from the President’s heart," Biden said in 2017 after Obama awarded him with the Presidential Medal of Freedom. "Mr. President, you have creeped into our heart -- you and your whole family, including Mom -- and you occupy it.  It’s an amazing thing that happened.  I knew how smart you were.  I knew how honorable you were.  I knew how decent you were from the couple years we worked in the Senate, and I knew what you were capable of.  But I never fully expected that you’d occupy the Bidens’ heart, from Hunter, to Ashley, my sister, all of us.  All of us."

The emotional remarks, which included Biden tearing up, underscored Biden’s long political career, serving as a Delaware senator for nearly four decades before his eight years as vice president, and spurred headlines that Biden was an "effective" veep who left behind a "legacy of hard work." 

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Biden receiving award from Obama

Then-President Obama awards Vice President Joe Biden the Presidential Medal of Freedom during a tribute to Biden at the White House in Washington, D.C., on Jan. 12, 2017. (Photo by NICHOLAS KAMM/AFP via Getty Images))

Though an admitted "gaffe machine," including describing Obama to a reporter as "the first mainstream African American who is articulate and bright and clean and a nice-looking guy" ahead of the 2008 election, Biden did not face nearly the same wave of criticisms as he does today over his near-daily gaffes, as well as new concerns over his mental and physical health. 

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Videos from his vice presidency era show Biden speaking in the same confident tone he held throughout his Senate career, as well as footage showing him easily striding up Air Force Two’s stairs, making coherent quips while speaking to crowds and overall employing his "Scranton Joe" demeanor as a relaxed politico representing average Americans. 

Joe and Jill Biden on Air Force Two in 2015

Then-Vice President Joe Biden with his wife Dr. Jill Biden wave to the press upon their arrival at the Guatemalan air force base in Guatemala City on March 2, 2015. (Johan ORDONEZ / AFP)

"Man, yeah, it feels great. I've always loved to drive," Biden told Jay Leno while driving his ’67 Corvette Stingray in a segment on "Jay Leno’s Garage" in 2016. "I shouldn't say this on TV … I like speed." The clip showed the then-VP doing a burnout with the car, which he said was a wedding gift from his dad, and bonding with Leno over their love of flashy and fast cars. 

Another video from Biden’s vice presidency showed him easily climbing up the steps of Air Force Two, delivering an optimistic 2012 DNC speech highlighting "America’s best days are ahead of us," and his resolutely pro-America DNC speech in 2016 that was lauded as making "patriotism liberal again."

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Joe Biden during 2016 DNC

Vice President Joe Biden addresses the delegates from the podium during the third day of the 2016 Democratic National Nominating Convention in the Wells Fargo Arena. (Mark Reinstein/Corbis via Getty Images)

"We do not scare easily, we never bow, we never bend, we never break when confronted with crisis. No, we endure, we overcome and we always, always, always move forward," he said of the United States' strength at the 2016 DNC. "That's why I can say, with absolute conviction, I am more optimistic about our chances today then when I was elected as a 29-year-old kid to the Senate."

"We are America, second to none, and we own the finish line," he said, impassioned. "Don't forget it."

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Joe Biden at podium during 2012 DNC

Vice President Joe Biden pauses while speaking during day three of the Democratic National Convention in Charlotte, North Carolina, on Thursday, Sept. 6, 2012. (Photographer: Daniel Acker/Bloomberg via Getty Images)

Outside of Biden’s official speeches supporting the Democratic Party and its allies, Biden, while vice president, was also seen on camera speaking coherently and relaxed to everyday Americans. 

"So here’s the deal, I’m coming for ice cream," he said in a 2010 call, for example, to an ice cream parlor that benefited from the Recovery Act small business loan. 

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Italian PM Giorgia Meloni brings back wandering Joe Biden

Italian Prime Minister Giorgia Meloni directs President Biden during a G-7 event.  (Fox News/POOL)

Fast-forward to 2024, the White House and Biden campaign are near-daily staving off criticisms and concerns regarding the president’s miscues and gaffes during public events as speculation mounts surrounding the president’s health.

Those most recently include: former President Obama taking Biden’s wrist to seemingly lead him offstage at a fundraiser in Los Angeles in June; Italian Prime Minister Giorgia Meloni directing Biden back to a gaggle of world leaders in Italy last month after he took a few steps away from the group to give a thumbs up to a parachutist; and viral video showing the president standing relatively motionless during a Juneteenth concert event at the White House. 

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Obama helps Biden leave stage

President Obama, right, takes President Biden by the wrist at a fundraising event. (Christopher Gardner via Storyful)

The White House slammed such videos as "cheap fakes" promoted by the Trump campaign and its allies, birthing a new 2024 campaign buzzword that was soon mocked by conservatives on social media as the administration "gaslighting" Americans. Cheap fakes, under the White House's definition, are understood as real videos that are cropped or edited in an allegedly deceptive manner. 

The Trump campaign last week demanded the White House and campaign apologize for the phrase and accusation, citing Biden's Thursday debate performance as evidence that "everyone sees there’s NOTHING fake about Biden’s decline."

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Joe Biden during June 2024 presidential debate

President Biden during the first presidential debate with former President Trump in Atlanta on Thursday, June 27, 2024. (Photographer: Eva Marie Uzcategui/Bloomberg via Getty Images)

Thursday’s debate was riddled with Biden tripping over his words, speaking in a far more subdued tenor than during his vice presidency, having a raspy and unsure voice and losing his train of thought at times. The debate unleashed panic among Democratic allies and members of the media, as they remarked his debate performance was a failure that added fuel to the fire surrounding concerns about Biden’s mental acuity and age. 

"My phone really never stopped buzzing throughout. And the universal reaction was somewhere approaching panic," MSNBC's Joy Reid, for example, said.

"The people who were texting with me were very concerned about President Biden seeming extremely feeble, seeming extremely weak," she continued. "Joe Biden’s job was to reassure them tonight. His job was to calm his party, to make them feel that, ‘Yes, I can do this. I have four more years in me. I have the ability and the stamina and the strength to do four more' … He did not do that. He did the opposite of that."

Biden's mental fitness has become a focal point this election season, with Trump routinely slamming the president for his garbled language in public remarks and repeated instances of Biden appearing confused while trying to find an exit off of a stage after public events. 

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In addition to his more recent gaffes and miscues, Biden has previously slipped while trying to board Air Force One, fell during the graduation ceremony at the United States Air Force Academy last year, declared "we can't be trusted" during a speech in April, appeared to forget the name of terror group Hamas in February, capped off a gun control speech last year with by saying "God save the Queen, man," and appeared to nap during a climate conference in 2021. 

Biden did come under scrutiny during his vice presidency for gaffes and questionable off-the-cuff remarks to reporters, but concerns regarding his mental acuity were not floated until he made his way into the 2020 presidential election, beginning with concerns over his age. 

When asked for comment regarding videos showing the president during his vice presidency compared to his presidency and debate, the Biden campaign pointed to the president's long list of campaign events following the debate. 

"President Biden met with supporters at 3 separate events across two states until 2:30am after the debate. He then did 3 more campaign events the following day. Meanwhile, Donald Trump held just one campaign event with supporters late in the afternoon on Friday," the campaign said. 

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Biden being helped up after tripping

President Biden is helped up after falling during the graduation ceremony at the United States Air Force Academy, just north of Colorado Springs, in El Paso County, Colorado, on June 1, 2023. (Photo by Brendan Smialowski / AFP)

Earlier this year, special counsel Robert Hur’s report investigating the president's handling of classified documents after his departure as vice president under the Obama administration further compounded concern over the president’s mental acuity

Hur announced in February that he would not recommend criminal charges against Biden for possessing classified materials after his vice presidency, calling Biden "a sympathetic, well-meaning, elderly man with a poor memory."

Again, the Biden administration and campaign faced more controversy over the president’s age and mental fitness when the Wall Street Journal published a bombshell report last month detailing interviews with roughly 45 lawmakers and administration officials on Biden's mental state, which caused alarm that the oldest sitting president in U.S. history is showing his age in meetings.

The White House hit back that the story and anecdotes were examples of partisan politics working to deride the "savvy and effective" president.

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Biden speaks outside White House

President Biden takes a question from a reporter before boarding Marine One on the South Lawn of the White House in Washington, D.C., on Tuesday, Jan. 30. (AP/Andrew Harnik)

Following Biden’s debate performance on Thursday, voters, critics, and doctors sounded off that Biden’s mental acuity is on a downward spiral that is on full display for the world. 

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Jackson, who has been a vocal critic of Biden's stretching back to the 2020 election, added in a comment to Fox Digital that Biden "sure as heck isn’t fit for the job moving forward."

"I’ve gone to no lengths to hide my true opinions about Joe Biden and his policies that are wrecking our country. In tandem, I have consistently shared my concerns as a former doctor of three United States Presidents regarding his fitness for office. Joe Biden was never fit for the job, and he sure as heck isn’t fit for the job moving forward. It is absolutely crazy to think he could lead this country 4-year term as our President," Jackson continued in his comments to Fox Digital. 

"Throughout the evening, Biden struggled to maintain a coherent narrative, often losing his train of thought mid-sentence, and providing vague, rambling and undecipherable answers to highly critical questions," Dr. Brett Osborn, a Florida neurosurgeon who specializes in cognitive function, previously told Fox News Digital.

"His difficulty in articulating clear, concise responses and his apparent disorientation during the debate were seen by many – including his own constituents – as very troubling indicators of his overall health and an obvious decline in his cognitive function," Osborn said.

Joe Biden at Juneteenth concert in June 2024

President Biden during a Juneteenth celebration at the White House. (Fox News/POOL)

While Dr. Marc Siegel, a clinical professor of medicine at NYU Langone Medical Center and a Fox News medical contributor, described Biden’s performance as "meandering," noting that he ended sentences in different places than intended, and "often mixed up ‘trillions’ and ‘billions’ and ‘millions.’"

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"The debate is, in a way, a psychiatric or cognitive stress test," he previously told Fox News Digital. 

Critics on social media also compared Biden on Thursday to how America previously knew him as a vice presidential candidate and later a presidential candidate in 2019, echoing the sentiment that "the rapid decline is clear." 

Biden’s 2012 vice presidential debate against Republican Mitt Romney’s running mate Paul Ryan was a success for the Obama-Biden ticket, with Politico declaring in a headline at the time that "Joltin’ Joe Biden wins the bout," the Daily Beast reporting that Biden’s performance that year "Perfects Art of the Smirk" and the Guardian reported Biden flaunted an "alpha-male display."  Other outlets hit back that Biden had a "laugh-filled" debate that was condescending at times, but no one floated concern the veep was losing his mental edge. 

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Joe Biden smiles during 2012 VP debate

Vice President Joe Biden smiles during the vice presidential debate at Centre College on Oct. 11, 2012 in Danville, Kentucky. (Chip Somodevilla/Getty Images)

"Stop talking about how you care about people," Biden shot at Ryan during the debate as the two sparred during the 90-minute debate. "Show me something. Show me a policy. Show me a policy where you take responsibility." 

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Joe Biden during VP debate in 2012 with Paul Ryan at right

Vice President Joe Biden, left, and Republican vice presidential candidate U.S. Rep. Paul Ryan (R-WI) participate in the vice presidential debate as moderator Martha Raddatz looks on at Centre College on Oct. 11, 2012 in Danville, Kentucky. (Chip Somodevilla/Getty Images)

In 2024’s presidential debate, Biden was hard-pressed to deliver a similar zinger at Trump, with traditional allies of the Democratic Party arguing one of his strongest responses to Trump was when he charged, "You have the morals of an alley cat." 

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Amid Biden falling over his words throughout the debate, Trump even flamed Biden for not understanding his argument when pressed about the immigration crisis. 

Joe Biden grimacing in closeup shot from CNN debate

An Axios report explained that Americans were so shocked by President Biden's debate performance because they are more used to seeing a more competent version of him. (Getty Images)

"What I’ve done since I’ve changed the law, what’s happened? I’ve changed it in a way that now you’re in a situation where there are 40% fewer people coming across the border illegally. That’s better than when he left office, and I’m going to continue to move until we get the total ban on… The total initiative relative to what we’re going to do with more border patrol and more asylum officers," Biden said when asked about immigration during the debate

"I really don't know what he said at the end of that sentence, I don't think he knows what he said, either," Trump shot back. 

Following the debate, Biden and his allies went on a media blitz defending the president. Biden also notably made a handful of campaign events in North Carolina, New Jersey and New York, where he vowed to fight harder to retain the White House. 

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"I didn’t have a great night, but I’m going to be fighting harder," Biden told the several dozen people at a New Jersey fundraiser. 

"Research during the debate shows us converting more undecided voters than Trump did, in large part because of his conduct on Jan. 6," he added. "People remember the bad things during his presidency."

Fox News Digital's Aubrie Spady, Melissa Rudy and Angelica Stabile contributed to this report.