Hoi,
For the majority of US states and territories (eg
Kentucky ) I have added the dates of governors holding office to Wikidata. This information is based on lists from the English Wikipedia. So you can follow the transition from the different parties (do not forget parties like the Wiggs).. When this information is complete I hope to bring this into a query that shows the US states and territories with maps; a colour change for the political party and a link that shows the politicians in power at that time.
Sure there are other functions like senators, representatives lieutenant governors.. they can be included. It is however a relevant start.
Thanks,
GerardM