For at least the past four years, President Joe Biden's White House and media allies worked to disguise and downplay the growing evidence of his physical and mental decline, only for it to become glaringly obvious following a disastrous debate performance in June.

On Sunday, a CBS News reporter remarked that Biden's "obvious cognitive decline" was, in her view, the most "undercovered and underreported" media story of the year, according to the New York Post.

Indeed, it took Biden's figurative collapse in the debate against President-elect Donald Trump for much of the media to finally begin reporting on what millions of Americans had suspected for years -- that the elderly president no longer had the necessary mental capabilities to effectively lead the nation for another four years.

Biden's "obvious cognitive decline" missed by the media

On Sunday's year-end edition of CBS News' "Face the Nation," guest host Major Garrett engaged in a lengthy panel discussion with some of the network's top correspondents on a range of different issues and stories.

At one point, Garrett asked his colleagues, including chief legal correspondent Jan Crawford, for what they believed was the biggest "undercovered or underreported" story of the year.

"Undercovered and underreported, that would be, to me, Joe Biden's obvious cognitive decline that became undeniable in the televised debate," Crawford replied. "Unquestioned."

"And it's starting to emerge now that his advisers kind of managed his limitations, which has been reported in The Wall Street Journal, for four years," she continued. "And yet he insisted that he could still run for president."

Biden White House was "delusional" or "gaslighting"

"We should have much more forcefully questioned whether he was fit for office for another four years, which could have led to a primary for the Democrats," CBS correspondent Crawford said of President Biden and the White House coverup of his declining mental capabilities. "It could have changed the scope of the entire election."

"Yet still, incredibly, we read in The Washington Post that his advisers are saying that he regrets that he dropped out of the race, that he thinks he could have beaten Trump," she added. "And I think that is either delusional or they're gaslighting the American people."

Ironically, one of the other CBS News correspondents engaged in the roundtable discussion, chief election and campaign correspondent Robert Costa, seemingly revealed that he had either fallen for the delusion or was a part of the gaslighting as he proferred up one of several lame excuses provided by the White House for Biden's exceptionally poor debate performance in June.

"President Biden has said repeatedly he was sick during the debate June 27 in Atlanta and he's always been fine and he leaves fine," Costa asserted. "That is his position, the position of many of his top aides as well, even though there is that reporting."

Other stories the media missed

To be sure, there were a multitude of major stories over the past year that were egregiously "undercovered or underreported" by the media, and the other CBS News correspondents offered up a few possible suggestions for which one should top the list.

Costa opined that it was the political "battle for working voters" and union votes that traditionally go predominately toward Democrats but were split by President-elect Trump, while political correspondent Caitlin Huey-Burns said it was the underestimation of how women voters would vote for the choices of Trump or Vice President Kamala Harris.

Meanwhile, congressional correspondent Scott MacFarlane suggested that the upcoming "size and scope" of Trump's planned pardons for Jan. 6 defendants had been overlooked by the media, while senior White House correspondent Ed O'Keefe surmised that the media hasn't looked deep enough into why so many migrants are drawn to illegally enter the U.S.