Pretty damaging, I think. Not now, maybe, but an outlet as mainstream and Democrat-friendly as CNN has already noticed the pace at which they’re happening, as you’ll see below. Imagine Iowans going to caucus six months from now having digested three new Biden mistakes per week every week since summer. How many undecideds will want to roll the dice on grandpa for a grueling general election campaign instead of the much sharper Elizabeth Warren or Kamala Harris?

The first and third errors there are self-explanatory. The middle one about Parkland is a chronological error: He wasn’t vice president when the Stoneman Douglas shooting happened.

“Note to Biden Backers: A Senescent Gaffe Machine Might Not Be the Safest Bet,” writes Eric Levitz today at New York mag:

Thus far, Biden’s Democratic rivals have been too polite to make an issue of the candidate’s increasingly conspicuous senescence. But some of his allies have been more forward; in interviews with the New York Times last month, “some of Mr. Biden’s own donors” evinced “significant unease about Mr. Biden’s ability to be a reliably crisp and effective messenger against Mr. Trump.

”Meanwhile, the Trump campaign has already demonstrated that it can and will work to disqualify Biden, one gaffe at a time. The most widely shared clip of Biden’s “poor kids” slip-up on progressive Twitter Thursday night was packaged by the president’s official rapid-response director. On Saturday, Trump himself called out Biden’s “truth over facts” flub…

None of [the other] candidates inspire euphemistic whispers about whether they’ve “lost a step.”

It is true, as David Axelrod noted a few days ago, that putting his foot in his mouth isn’t a habit Biden acquired in old age. His best defense to whispers about senility would be to note, accurately, that he’s been saying dumb sh*t for decades. But it’s also true that, a la 2016, Democrats might be on the brink of nominating someone uniquely ill-equipped to prosecute the case against Trump. Trump ran on a populist “drain the swamp” message in 2016, to which Dem voters responded by nominating … one of the swampiest, most unpopular figures in their party. Biden’s long track record in Washington would give Trump’s populist message some renewed vitality, allowing a sitting president to potentially run as an “outsider” a second time, but more importantly the concerns about his age would help neutralize voters’ concerns about Trump’s own fitness for office. It should be easy to run against a guy who amplifies something like this after a federal prisoner dies in the custody of his own Justice Department, as Trump did by retweeting it on Saturday afternoon…

…but if Trump gets through four years with a strong economy and without starting any wars, lots of voters will rationalize the tweets by telling themselves they’re just a sort of harmless release valve for him where he can indulge his inner crank without hurting anyone. Meanwhile, Team Trump will magnify every errant word out of Biden’s mouth in order to redirect attacks on Trump’s fitness back at Democrats: “You say our guy’s a mental defective? *Your* guy’s the real mental defective.” Righties already ran a variation of that strategy in 2016, in fact, by cutting and circulating viral clips every time Hillary had a coughing fit. The Trump approach then and now isn’t so much to sell the electorate on his strengths as to present him as the lesser of two evils to swing voters, no less fit for office — physically and morally — than the competition.

Biden could end up making that easy for them. One truly bad gaffe in a big spot next year that can’t easily be explained away as a simple verbal flub might raise enough doubts in voters’ minds as to tilt undecideds towards Trump. “We survived four years with him in charge, we can survive eight. The other guy seems not to know where he is anymore.”

All of which explains why Biden’s Democratic opponents will inevitably start raising this as an issue this fall, however much they may have to talk around the subject of his age. One candidate already did so at the first debate, in fact, and ironically he’s the one candidate who’s since dropped out of the race.

The two pillars of Biden’s campaign are his support among black voters as Obama’s VP and his perceived electability, a metric in which he continues to utterly crush the field in polling. Kamala Harris tried to knock down the first pillar in the first debate by attacking Biden on busing and succeeded in getting some of those black voters to waver for awhile, but at last check they were back on Team Joe. The obvious move now is to try to knock down the second pillar, and one equally obvious way to do it is to suggest that Biden doesn’t have the, ahem, “stamina” to endure 15 more months on the trail, especially against an opponent as nasty as Trump. Dem voters prefer him right now because they know that he’s polling better against POTUS than anyone else. Seed some doubt in their minds about whether that trend would hold after 100 more gaffes that call Biden’s mental acuity into question and they’ll start to soften up.

I’ll leave you with this:

One aunt said something my mother said to me nearly a year ago. That it’s going to take a white man to straighten out the mess we’re in. “The way the system is set up now, there is so much racism that it’s going to have to be an old white person to go after an old white person,” my aunt told me. “Old-school against old-school.” She talked further about what this meant for younger candidates such as Buttigieg. “The whole world is in a crazy state, and somebody’s gotta put it back in order. And I think a lot of the young people who want to put it back in order, want to change it completely,” she continued. “But first, you’ve got to put it back in order before you can start changing it.”

Which way does that cut? Is an experienced old white guy still the best bet for Dem voters even if he’s “lost a step,” or does the perception that he’s lost a step start to shake Dems’ faith in Biden’s ability put the world “back in order”?

Update: No sooner did I finish this post than this clip (from CNN again) began making the rounds. Harris isn’t ready to accuse Grandpa Joe of having lost a step. Yet.