There’s definitely a cross section of highly biased and partisan supporters that could have swung either direction at some point in their life if they had hung out with different people.

Almost every person on earth could have swung in any direction if they had hung out with different people. If you or I hung out with Ancient Egyptians our whole lives we would have thought burying kings with living slaves was about as normal as surfing Hacker News.

which holds the implication that people as an abstract between now and ancient Egypt are not actually that different. They're just responding to different stimuli in their respective environments.

yes, on biological basis it is true that Republicans and Democrats are pretty similar. They are in fact the same species. Even if Democrats in 2019 might be statistically more likely to have genes for sickle-cell Anemia... is that relevant?

I think the relevant questions are:

- "What are the mindsets they've actually absorbed over their lives?"

- "How do they evaluate evidence?"

- "How do they evaluate the competence and character of judicial and executive appointees?"

- "Whom do they rely on for expertise?"

- "How do they reason about the role of government?"

- "How do they design policies?"

- "How do they spot potential unintended consequences?"

- "How do they communicate with constituents?"

- "Whose perspectives do they believe it is important to consider?"

- "Whom do they consider key to re-election?"

That's an implication a lot of people will do a lot of mental gymnastics to avoid because it means you can't just ignore the misadventures of various societies throughout history by saying "we're smarter now" or something like that.

None of the educated people I know would think “we’re smarter now” after studying history.

If someone dismissively thought "we're smarter now", would they bother to study history?

Which speaks to exactly how arbitrary the two parties and their loyalties are.