Similar to a lawyer telling a client to just repeat, “no comment,” the Harris team just needs to keep saying “He agreed to this debate and Kamala will be there. The Fox debate was only brought up after he reneged on his previous commitment. We will not be at Fox as it was never in the schedule. We can discuss a Fox entertainment debate after this previously scheduled debate takes place. Next question.”

Say nothing else and just repeat that ad nauseam.