Cruz’s strength in the primary was the suburbs. He won Collin, Denton, and Montgomery counties and fought Dewhurst to a draw in Fort Bend. Dewhurst underperformed in the cities and the suburbs but swamped Cruz in rural Texas.

Collin County:

Cruz 35.45%

Dewhurst 30.65%

Denton County:

Cruz 34.73%

Dewhurst 31.42%

Montgomery County:

Cruz: 46.80%

Dewhurst 38.34%

The urban counties were virtually a dead heat:

Harris:

Dewhurst 45.89

Cruz: 43.58

Dallas:

Dewhurst 33.94%

Cruz 31.145%

(Leppert 30.92%)

Tarrant County:

Dewhurst 35.21%

Cruz 33.65%

Bexar County:

Dewhurst 40.75

Cruz 39.21 

So why did Cruz trail Dewhurst by a significant percentage in the primary (Dewhurst 44.67%, Cruz 34.09%?) statewide?

The answer is twofold. One is that Dewhurst’s momentum collapsed in the last days of early voting and on election day, while Cruz’s continued to build. The other is that Dewhurst strongest support came from rural Texas. He crushed Cruz in rural counties. Some sample counties:

Hale (Plainview):

Dewhurst 60.33%

Cruz: 28.98%

Brown (Brownwood):

Dewhurst 57.40%

Cruz 28.98%:

Bell (Belton)

Dewhurst 49.42%

Cruz 38.43%

Harrison (Marshall):

Dewhurst 50.07%

Cruz 26.85%

Hays (San Marcos):

Dewhurst 41.32%

Cruz 32.60%

Hays is partly rural, partly suburban.

As a broad generalization, I would say that any runoffs in urban and suburban areas should bring more Cruz voters to the polls; any runoffs in rural areas should bring more Dewhurst voters to the polls.