How does proximity affect politics?

It has been a point of fascination to me that most US cities lean left, as demonstrated in this Wikipedia article:
"As of 2025, of the mayors of the 50 largest U.S. cities, 38 are Democrats (76%), 9 are Republicans (18%), and 3 are Independents (6%).[23] In 2016, the average Trump support in farm-heavy counties was 73%; it was 76% in 2020; it was 78% in 2024, when he won all but 11 of these 444 counties."

What accounts for this profound difference? Is it the necessity of getting along with neighbors, or that those neighbors may be of a different ethnicity or nationality? How does the population density of your surroundings influence your politics?

I think this is a great topic for our group, so let's gather in our usual spot for a little discussion about how proximity influences our politics.

Don't forget to update your RSVP and bring a dollar for the event fee. Hope to see you there!