Harris's dilemma is that Trump is a known quantity and will secure his vote whatever the circumstances; whereas she is still ill-defined...but defining herself might put as many, if not more, people off than if she avoids doing a lot of tv interviews to present herself more fully.
The rejection of a second debate with Trump hurt her chances big time. She was able to make Trump look clumsy in the debate they did have.
Still on a knife edge this one though. Harris and Trump in the swing states have only very small leads over each other and it'll all turn on Harris breaking through as a realistic leader - hard to do when Genocide Joe is still in office making (poor) decisions - and sealing a deal with the undecided's in those swing states....which is why I think the Walz choice of VP has done her no favours, as he looks out of his depth whereas a Newsom would have been a slick presentational choice to offset Vance.
Say you know nothing about American politics without saying you know nothing about American politics
Newsom certainly has the chutzpah to beat down Vance in a debate of slick snake oil salesmen, where debate style matters more than substance or whether you're saying anything remotely truthful. So Newsom would have beaten Vance at his own game in a debate. Great for our feelings, no doubt.
But VP debates are meaningless in the context of a presidential election, unless you're someone on the order of magnitude as a Sarah Palin.
Walz comes across as the virtual opposite of someone like Vance. And that's good thing in the context of this presidential election.