Parties (“partisanship”) are only rough approximations for two differing human mindsets about how humans should provide for their basic human needs.
There are “foragers” (hunter/gatherers) and there are “producers” (farmers/herders).
Foragers are mentally and socially primitive. They are tribal and place all their loyalty and trust in the tribal “shaman”. The shaman talks to the spirit world and knows the answers to all the important questions. Tribe members DON’T have to think for themselves, and in fact, thinking for oneself is disloyal to the shaman and subversive.
Producers are mentally advanced and have used their evolved brain capacity to understand the processes of nature and the orderly predictable ways that things can change over time. Producers produced surplus food, learned the logic and advantages of trade over tribal warfare, and developed the capacity to independently think in multiple dimensions to solve complex problems.
Differences between Democrats and Republicans are not based on “partisanship” but result from the evolutionary reality that one group views independent thinking as “anti-tribal” and therefore anti-social, and the other group views it as enabling individual and social prosperity and security.
The problem is not “partisanship”, it’s evolutionary divergence.