I actually want to expand on this and why I think Harris is having so much of a popular surge right now: politics really is about telling a story, and if more people believe your story than the competing ones, you win. Policy positions are important, of course, but as part of that story, mostly.

Trump's campaigns have always told a very dark and ugly kind of story- we are a fallen nation, we are humiliated and abused by the rest of the world, but under Trump's leadership, we will be redeemed and our troubles will get a fairytale ending where we win forever.

Even Nazism paid lip service to a utopian future, where Germans conquer Europe (and probably the rest of the world) and the German people would live in grand cities and benefit from technology (and also be forced to engage in large scale gladiator battles, but let's not focus on that).