What this means isn't yet definitive. But here's what these three Texas counties have in common:

1. All are suburbs of heavily Democratic metro area (Dallas and Austin)

2. Their populations have exploded

3. They voted for Trump in 2016, but shifted dramatically left in 2018 https://t.co/AoZC3uW02o

— Brandon Friedman (@BFriedmanDC) October 26, 2020