It was expected that Joe Biden was going to be a gaffe machine on the campaign trail. That is, after all, the long-running joke about the avuncular former vice president—one that Democrats, and the Onion, generally found endearing right up until the moment Biden launched his third presidential run. Still, the velocity of self-inflicted wounds has been remarkable, prompting whispers about Biden’s age (76) and mental agility. It’s not just his penchant for expressing antiquated views on political civility but also his spouting off confusing strings of numbers during the last debate. The gaffes seemed to accelerate in the past week, beginning with a bungled remark about how “poor kids” are just as smart as “white kids,” mixing up Theresa May (a living former British prime minister) with Margaret Thatcher (a dead one), repeatedly claiming that he met with the Parkland shooting survivors as vice president (Donald Trump was president at the time), and confusing the details of recent mass shootings.

Biden campaign insiders say the longtime politician is as physically and mentally fit as ever, but they also worry that the accumulation of gaffes is solidifying into a media narrative. The New York Times reports:

While his advisers dismissed the individual remarks as minor miscues that Mr. Biden mostly amended quickly, the slipups have become part of a pattern—a strong campaign trail moment, followed by a blunder that dominates the news coverage—that has been enormously frustrating to them and, some Democratic allies say, to Mr. Biden himself.

Some of his advisers said in interviews that they were privately nervous that his recent gaffe spree would become cemented into the larger narrative of the presidential race. They also say that Mr. Biden faces an unfair double standard.

So far, few of Biden’s Democratic rivals have been willing to broach the subject of his seniority, except obliquely. (Eric Swalwell, the only candidate to take a swipe at Biden’s age, in the first debate, has since withdrawn from the race.) But Trump appears eager to feed the narrative, which might have the effect of neutralizing some of the criticism of the president’s own apparent cognitive decline. After all, he’s done it before, aggressively undermining Hillary Clinton by running ads suggesting she was in poor health—an attack she literally stumbled into after she collapsed while leaving a 9/11 memorial service.

Biden’s backers insist nobody cares about this malarkey except his rivals, the media, and a Republican Party eager to damage the front-runner before he even gets to Trump. They also say the best way to counter the gaffe narrative is more Biden, not less. “Getting Joe Biden to meet people is the best thing for the Joe Biden campaign,” pro-Biden Representative Filemon Vela of Texas told the Times, citing a recent, grueling, nearly two-hour meeting with the Congressional Hispanic Caucus. “Nobody in that room left concerned about his ability to beat Donald Trump.” Prospective 2020 voters feel much the same way. Current polling puts Biden at an average 8.5-point advantage over Trump in head-to-head matchups.