A Kamala Harris / Mark Kelly ticket will demolish Trump and Vance.
Harris will hammer Trump on abortion and women's reproductive rights, which lost Republicans seats in Red states during the midterms. She'll also reinforce him being held liable for rape by a court. I think She'll better articulate the successes of the Biden admistration, while continuing to go on the attack vs Trump in the areas he can't defend. The areas that offend voters in the U.S.
Meanwhile, Mark Kelly's record is nearly untouchable. Elected a blue Senator in a purple state. A seat Democrats hadn't won since 1962. 30 year military veteran. Naval combat pilot with 39 combat missions in Iraq and Afghanistan. 2x Distinguished Flying Cross recipient. 2x astronaut with NASA, including pilot and mission commander of space shuttle Endeavor. Commander of the International Space Station. Wife is a Senator who survived an assassination attempt in 2011 after being critically wounded. He's extremely intelligent, well spoken, articulate and well liked. Only 60 years old and in excellent health... Neither Trump nor Vance could say a bad thing about the guy without alienating half their voting base that are pro military and all of whom dreamed of growing up to accomplish 10% of what Mark Kelly has done in his life time.
That ticket deeply appeals to the average American, who holds typical American values.
I'm going to be nice but this is optimistic at best.
Aside from the fact that Kamala Harris couldn't debate a preschooler and come out looking good, very few people in the US actually give a crap about abortion any more. The mid-terms were when the issue was still fresh on the agenda and even then it didn't give the Democrats any particularly major wins. It's been 2 years since then and the entire issue of Roe v. Wade was giving power over abortion rights back to the states - and most red states have already affirmatively clarified its legal status so it's not really a hot topic anymore.
The actual legal system tried to nail Trump on rape charges and failed. Kamala wouldn't be doing anything there that Trump hasn't already been face-to-face with. She'd also be pretty hard-pressed to espouse the virtues of the Biden administration given how few there are and Trump's debating style is basically going fully on the offensive and smashing his opponent over every single fuck-up. And Biden has a LOT of those. Hell, Kamala herself has a fair amount of them.
I'm not sure what you think the average American is like but Mark Kelly being a veteran means absolutely fuck-all. The left-wing doesn't give a crap or actively dislikes what they perceive as army goons and the new right-wing is long past the period of putting military personnel on a pedestal after decades of such political types repeatedly letting them down. Kelly also earned a lot of ire for repeatedly trying to hide behind his wife's attempted assassination - 13 years ago - to deflect criticism. Not to mention that he has an obvious weak point that Trump will hammer, which is his connections to China.
Harris is a bad choice all round and no matter what kind of VP she picks, she's not going to win. To the average Joe and Jill, she's only slightly more palatable than oatmeal laced with cyanide for breakfast.
It's one of the reasons why Democrats have been so desperate to keep Biden in the game despite his blatantly obvious mental deterioration. He may be a dementia-afflicted fossil but he still holds marginally more appeal than Kamala does. But it's gotten to the point where it's simply not possible for grandpa to keep fighting any more so they have thrown in the towel and are now desperately praying that Kamala doesn't screw up too badly.
