>That the city sprawls like crazy is more of a red Texas artifact.
It's actually an artifact of Houston's original charter which allowed nearly unlimited growth via annexation and Houston's use of that annexation power to reclaim its tax and voter base each time they moved outward from the city center. Houston grew from 9 square miles in 1900 to ~600 square miles today. See http://www.chron.com/local/history/major-stories-events/arti... for more details.
Blue dots surrounded by red also happens in California (and indeed, in any state with cities). It’s just that the blue dots are much more dense in California.
I don’t think there is such a thing as a red big city.
It's actually an artifact of Houston's original charter which allowed nearly unlimited growth via annexation and Houston's use of that annexation power to reclaim its tax and voter base each time they moved outward from the city center. Houston grew from 9 square miles in 1900 to ~600 square miles today. See http://www.chron.com/local/history/major-stories-events/arti... for more details.
As to our voting patterns, see https://www.texastribune.org/2016/11/11/analysis-blue-dots-t... for analysis. We're generally a blue dot surrounded by red but that's on average.