Joe Biden’s aptitude for gaffes and unforced errors returned this week, playing into the hands of the Trump campaign and creating stirrings of nervousness among Democrats.

The presumptive Democratic presidential nominee apologized Thursday for comments he made the day before suggesting the African American community lacked diversity.

Biden had initially said, “Unlike the African American community with notable exceptions, the Latino community is an incredibly diverse community, with incredibly different attitudes about different things.”

In a late Thursday tweet, he clarified, “In no way did I mean to suggest the African American community is a monolith—not by identity, not on issues, not at all.”

Biden, 77, also got into a heated exchange with Errol Barnett of CBS News after Barnett asked him whether he had undergone cognitive tests like the one President Trump, 74, has bragged about passing.

After saying he had not, Biden added heatedly, “Come on, man. That’s like saying to you, before you got on this program if you had taken a test, were you taking cocaine or not? What do you think, huh? Are you a junkie?”

The awkwardness of the moment was compounded by the fact that Barnett is biracial, and slurs of drug use are often seen as a form of racial stereotyping.

Though neither of the miscues are campaign-changing, they add a level of unease even among some people desperate to oust Trump from the White House.

Jonathan Tasini, a progressive strategist who supported Sen. Bernie Sanders (I-Vt.) in the Democratic primary, played down the effect of the slip-ups overall, arguing the average voter is far less interested in them than Beltway commentators.

Still, Tasini added, “The caveat is when these things he says reinforce to people, especially to those paying attention, concerns on race and other issues.”

In May, Biden said during a radio interview with Charlamagne Tha God, “If you have a problem figuring out whether you’re for me or Trump, then you ain’t black” — another remark that was widely criticized as tone-deaf.

The debate around Biden’s propensity for these kinds of slip-ups is a complicated one.

The Trump campaign is pressing such moments as examples of why the Democrat is unfit for the presidency, arguing the remarks are both patronizing to people of color and evidence of a lack of mental sharpness.

But there are numerous instances of the president either misspeaking or making much more racially offensive comments than Biden has done.

In the first category, Trump has within the past few days mispronounced both “Yosemite” and “Thailand,” drawing mockery on social media.

In terms of general tone-deaf remarks, Trump also said during an “Axios on HBO” interview broadcast Monday that the huge American death toll from COVID-19 “is what it is.” He has repeatedly claimed, against available evidence, that the coronavirus will “disappear.”

Trump’s record on racial matters includes talking about “very fine people on both sides” of racist violence in Charlottesville, Va.; reportedly branding nations in the Caribbean and Africa “shithole countries;” asserting that the four nonwhite Democratic congresswomen known as “the Squad” should “go back” to the “crime infested places” from which they “originally came,” despite all four being U.S. citizens; and tweeting, amid unrest following the death of George Floyd, that “when the looting starts the shooting starts.”

Given all that, it might seem an uphill battle for the Trump campaign to make much of Biden’s recent remarks. But it is trying.

Katrina Pierson, a senior adviser to the Trump campaign, said in a statement that Biden’s comments regarding diversity were “disgusting” and accused him of “condescending white liberal racism.”

GOP strategist Matt Mackowiak told The Hill that the missteps are “forcing the Biden campaign to decide whether to keep him in hiding or to make him available when these mistakes continue to happen.”

Such comments go to the broader debate about Biden’s mental acuity. That is by its nature a sensitive issue, and some who have sought to weaponize it have suffered political blowback.

During the Democratic primary process, a rival candidate to Biden, Julián Castro, received criticism when he raised the subject. During a September 2019 debate, the former Housing and Urban Development secretary asked Biden whether he was “forgetting” what he had said “two minutes ago.” Castro later denied he had been referring to Biden’s age.

Biden raised eyebrows last year when he said that “poor kids” are “just as talented as white kids” before quickly correcting himself to say “wealthy kids.” He also discussed meeting with the survivors of the Parkland, Fla., school shooting in his capacity as vice president — despite the fact that the shooting occurred more than a year after he left office.

During a speech at the Iowa State Fair last August, Biden said, “We choose science over fiction. We choose truth over facts.”

Grant Reeher, a professor of political science at Syracuse University’s Maxwell School, said that while Trump had said much worse than Biden in terms of “levels of offensiveness or levels of insensitivity or thoughtlessness,” the peril for the Democrat lay in a somewhat different area.

“It is less clear that Biden is saying those things on purpose. In other words, there is this sense that he is not fully in command of what he is intending to say. ... That’s where the potential problem begins to open up for him.”

The Trump campaign this week pushed for an additional debate beyond the three already scheduled, believing one-on-one comparisons between the two men will play to the president’s advantage.

Trump’s aides want an opportunity to debate Biden before early voting commences in earnest. But they are also cognizant of polls that show the president well behind.

Democrats such as Tasini insist that concerns about Biden in the debates may be overblown, in part because of his opponent’s penchant for misspeaking.

“[Biden] is, to put it mildly, not facing off against some orator who is sharp and coherent,” Tasini said.

For now, however, every new stumble puts a brighter spotlight on Biden. He has established his polling lead while allowing Trump’s mistakes to weigh the president down — and by keeping a low profile himself.

That will inevitably change, and it may yet inject the race’s closing months with some real uncertainty.

The Memo is a reported column by Niall Stanage, primarily focused on Donald Trump’s presidency.