Congress can, and periodically does, override presidential vetoes. If you've got the most conservative Republicans in the Senate on board, it sounds like an override is in the cards.
I put up a comment about it yesterday, but I'm predicting Oct 12- 16th for a pivot.
Specifically, these debates mostly nothing
At this point, if you were going for Trump, there is no debate performance that is going to change that. Likewise for Harris voters. As well, we're just about past the point where voter registration is going to change anything. Just about the last 2 weeks of September and the state which matter won't be accepting new registrations.
So it's down to people that are likely voters who are still withholding for some policy positions.
Realistically she's got quite a few of those, but when given a bad but not fundamentally different from what one had before option, and a make everything far worse option, and a situation that makes trying to choose a third option an exercise in futility, the choice is a no-brainer.