When parties are roughly evenly matched, elections often turn on irrelevant or misleading considerations such as economic spurts or downturns beyond the incumbents’ control; the outcomes are essentially random. Thus, voters do not control the course of public policy, even indirectly.
Which makes it all the more important for candidate not to pull a Harris and try to gaslight voters.
https://press.princeton.edu/books/hardcover/9780691169446/democracy-for-realists