The race for Texas for the Democrats will depend on Texas ten largest counties.
Harris alone is worth 15% of the total votes in Texas in 2016 and also in early voting 2020. Obama won Harris by 1% in 2008 and 2020. Clinton by 12% and O’Rourke by 16.7%. If Biden can win Harris by between 20 - 30%, that will be a game changer.
Then there is the turnout. Harris, Dallas, Tarrant, Bexar and Travis currently account for 49% of Texas early voting. Well ahead of 2016 where these five counties accounted for 42% of Texas total votes. Dallas voted Hillary +26%, Bexar +13% and Travis +38%. The biggest weakness is Bexar which tends to have low turnout when compared to Dallas and Travis. Even in 2020, although the county is doing better, it still lags behind Dallas and Travis.
This is where it gets interesting. Trump won Tarrant county by 8.5% in 2016. O’Rourke won Tarrant by 4,290 votes in 2018. There was an 8% shift in the parties balance of power in Tarrant between 2016 and 2018. If Biden can flip Tarrant that will be big.
Lets take a look at a couple more large Texas counties. Trump won Denton by 20% in 2016, Cruz won by only 8% (12% shift). Trump won Collin by 17% in 2016, Cruz won by 6% in 2018 (11% shift). Flipping Denton and Collin is probably a tall order. However, if Biden can close the gap, that will really help. The same with Montgomery and Williamson. If Biden can narrow the gaps to single digit that would be great.
The remaining counties, Fort Ben and El Paso are pretty solid Blue. El Paso voted for Clinton +44%. So turnout, turnout, turnout.