Why Texas still leans Republican, and comparing Arizona versus Nevada.KEY POINTS FROM THIS ARTICLE— We’re continuing our series of looking at how the most vote-rich counties in a state vote versus those that make up the rest of the state by moving to the Southwest.— The region contains the key swing states of Arizona and Nevada, both of which are dominated by a single county that casts well north of half the statewide vote.— Both the top and bottom halves of Texas have moved toward the Democrats from 2012-2020, but the top half just is not blue enough at the moment.— Colorado and New Mexico have moved out of the swing state category, pushed by top-half shifts.