Former President Trump sparked a new furor with comments over the weekend in which he disparaged Vice President Harris as “mentally impaired” and “mentally disabled.” The remarks —  coming initially at a Saturday rally in Wisconsin and repeated in broad terms the following day in Pennsylvania — have thrown Republicans onto the defensive, outraged Democrats and sparked condemnation from disability advocacy groups. But they also draw puzzlement from political insiders who believe Trump’s penchant for personal invective does him no favors electorally, serving only to turn off some of the undecided voters he needs to win over this November if he is to avenge his 2020 loss to President Biden. The sensitivities around Trump’s hyperaggressive rhetoric are particularly sharp when his opponent is female, Black and of South Asian descent. “I’m not sure how many people are really undecided at this point,” said John "Mac" Stipanovich, a veteran GOP operative based in Florida and a Trump critic. “But if there are any undecideds out there — making fun of the mentally handicapped? ‘Slagging’ women? I just don’t see how that helps you.” The Harris campaign hit out at the Saturday speech as emblematic of a bleakness they say often characterizes the former president’s speeches — even as the vice president’s aides did not directly reference Trump's attack regarding mental capabilities. “He’s got nothing ‘inspiring’ to offer the American people, just darkness,” campaign spokesperson Sarafina Chitika asserted in an email to reporters. Trump initially attacked Harris’s mental state in Prairie du Chien, Wis.  “Joe Biden became mentally impaired. Kamala was born that way,” Trump said, adding “and if you think about it, only a mentally disabled person could have allowed this to happen to our country.” He repeated the “mentally impaired” line, with minimal variation, the following day in Erie, Pa. The claim is self-evidently false. The 59-year-old Harris has not previously drawn skepticism, even from most of her political critics, about her cognitive abilities.  In that respect, she differs from the 81-year-old Biden and the 78-year-old Trump, who are prone to meandering or disjointed public comments that have raised such questions. Public concern about Biden in this regard was sharper than about Trump, even before the disastrous June debate that sparked the events that led to the president’s abandonment of his reelection bid. The attack by Trump may at some level be a symptom of his apparent difficulty in finding an effective way to attack Harris personally.  The former president enjoys finding derisive nicknames for his political enemies, but he has cycled through several — including “Kambala” and “Comrade Kamala” — for Harris, without seeming to settle on one. An Economist/YouGov poll last week found Americans evenly split — 48 percent on either side — on whether they viewed Harris favorably or unfavorably. Trump, by contrast, was viewed unfavorably by 56 percent and favorably by only 42 percent. The downside of Trump’s personal attacks is that they can backfire, reminding many voters of the reasons they dislike him. An NBC News national poll conducted in mid-September saw Harris lead Trump by 16 points when registered voters were asked which candidate had “the right temperament to be president.” The vice president led by an even greater margin, 20 points, when voters were quizzed on who had “the necessary mental and physical health to be president.” The same poll showed Trump with a 9-point edge on the central issue of who is more trusted to deal with the economy. Republicans, looking at polls indicating a small national lead for Harris and a toss-up in the battleground states, now confront a scenario in which Trump is preferred on voters’ top issue but could lose the election because his personal comportment is disliked by so many. Rep. Tom Emmer (R-Minn.) was asked by ABC News’s Martha Raddatz on “This Week” on Sunday whether he approves of Trump’s language alleging Harris is impaired. “I think we should stick to the issues,” Emmer responded. Sen. Lindsey Graham (R-S.C.), responding to the remarks in an interview with CNN’s Jake Tapper on Sunday’s “State of the Union,” appeared to agree Harris is not “mentally impaired” but added, “I just think she’s crazy liberal.” Even Graham acknowledged, however, that “I just think the better course to take is to prosecute the case that her policies are destroying the country.” The controversy, as so many Trump furors before it, has also drawn criticism outside the political community. Maria Town, the president and CEO of the American Association of People with Disabilities, said in a statement that Trump held “the ableist, false belief that if a person has a disability, they are less human and less worthy of dignity.” Town added: “To be clear, the insult of Donald Trump’s comment is not the suggestion that Vice President Harris is disabled, but rather, the insinuation that having a disability is synonymous with poor performance as a prospective president.” To be sure, there are innumerable past Trump controversies that have not adversely affected his popularity. It seems extremely unlikely that the latest furor will have any detrimental effect upon the former president’s Make America Great Again base. But no one outside that base seems to think that going after Harris in such personal terms is a good idea. The Memo is a reported column by Niall Stanage.