For the nurture side of the argument, location is a big one. If you are born in a certain area, you are more likely to vote one way rather than the other.
Urbanization. Urban areas that are densely populated, unfortunately, require "
BIG" government. The citizens of these areas "require" laws related to sanitation, pollution controls, building codes, noise control, transportation systems, how power is delivered to homes and businesses, health services, etc.
Unfortunately, the people in urban areas tend to vote Democratic. Overtime, increased urbanization and subsequent dependence on government services will mean that the Democrats will eventually control the US political system.
Why do you believe in the politics that you do? Is it because of reality, or due to your upbringing? Or, is it because of personality traits you have inherited that lean you towards a particular type of view?
We were, at least we were before 1965, taught civics in a positive pro-US manner. So my upbringing would continue to support these US traditions. However, as many have noticed many on the progressive left denigrate US culture and many have been influenced by that rhetoric.
A glaring example of this change in attitude are quotes from Kennedy, King, and Bill Clinton. Kennedy's quote paraphrased: ask not what your country can do for you, but what you can do for your country. King looked forward to when people would be evaluated on their character not not the color of their skin. Bill Clinton proclaimed that the era of big government was over. Today, those on the progressive left believe that the government owes them. That people should be considered for "x', "y", or "z" base on the color of their skin and not the content of their character. Big government continues to grow unabated in the face of incremental crises, such as 9/11 and the Covid-19 pandemic.