Reprinted with permission from MediaMatters

At the very end of former Vice President Joe Biden's press conference largely focusing on the Trump administration's botched response to the COVID-19 pandemic, Fox News reporter Doug McKelway pressed Biden about being tested for his mental capacity -- a constant theme of Fox News and the Trump campaign since Biden became the presumptive Democratic presidential nominee.

From the June 30, 2020, edition of Fox News' Outnumbered Overtime

DOUG MCKELWAY (FOX NEWS CORRESPONDENT): Some have speculated that you are subject to some degree of cognitive decline. I'm 65, I don't have the word recollection that I used to have, I forget my train of thought from time to time. You've got 12 years on me, sir. Have you been tested for some degree of cognitive decline?

McKelway, who has sent emails with white nationalist talking points and tweets attacking Democrats as "racial identity politics hucksters" while working at Fox News, seemingly ripped his question about a test about cognitive ability from the Trump campaign itself.

Moments Later, Fox anchor (and former George W. Bush press secretary) Dana Perino asked conservative radio host Chris Plante about Biden's remarks. Plante suggested that if Biden isn't in cognitive decline, then everyone else was.

From the June 30, 2020, edition of Fox News' The Daily Briefing

CHRIS PLANTE (RADIO TALK SHOW HOST): Honestly, if you don't think Joe Biden is missing a step -- if you, before today, didn't think he was missing a step -- you see why they've kept him under wraps, why they are keeping him under wraps. Doug McKelway asked the salient question, are you aware of any cognitive decline? If he's not, I think the rest of us are. When he attacks the president, for example, over the virus, President Trump was restricting travel from China and it was Joe Biden that was indicting him as a xenophobe for restricting travel from China. That would seem to indicate that Joe Biden would have done less.

The Trump campaign immediately blasted out the clip of McKelway's question as well.

At the top of the 3 p.m. "straight news" hour on Fox hosted by Bill Hemmer -- the hour which previously was helmed by Shep Smith -- McKelway reported from the scene, suggesting that Biden may have "mild dementia" based on widespread speculation, and that the press conference was the former vice president finally getting out of the basement:

From the June 30, 2020, edition of Fox News' Bill Hemmer Reports

DOUG MCKELWAY (FOX NEWS REPORTER): There is speculation, and it is widespread -- there is no hiding it anymore -- that based upon several gaffes that Biden has made in recent months and even in recent years, that he is experiencing the first effects of some sort of mild dementia or cognitive impairment.
...
MCKELWAY: More to come on that in the days and weeks as he now gets out of the basement so to speak, Bill.
BILL HEMMER (ANCHOR): You were one of the few reporters to get some news out of him, so good questions.

As Matt Gertz noted, McKelway is a right-wing hack:

Meanwhile, as noted in the transcript above, Fox anchor Bill Hemmer praised McKelway.