According to the Star-Telegram, the plaintiffs are arguing that if a 63% majority Anglo district happens to elects a Democrat at any time, the white Democrats and minorities are protected under the Voting Rights Act from any change that might disrupt that incumbent.  Thus, under these facts, a Republican can never and will never be a candidate of the district’s choice because of the 37% minority population.  Sounds like the Democratic Party Protection Act for white Democrats. 

The state’s expert witness, John Alford of Rice University, was on the stand to defend the districts drawn by the Texas Legislature for the Texas House, Texas Senate and U.S. House.
During questioning by Davis’ attorney — who maintains that Davis’ Tarrant County-based District 10 was carved up to keep blacks and Hispanics from voting for a candidate they prefer — Alford said that it was Anglo voters who gave her the win over a Republican incumbent.

“The deciding factor there was not the degree of change in voting by minorities,” Alford said. “It was clear that the deciding factor of what caused that to be a victory was the much higher level of Anglo crossover. The district is a majority Anglo district … about a 63 percent majority Anglo district.”

Alford said in an interview that according to racial voting patterns, “Anglos who vote Democratic in Texas are considered crossover voters.” In Tarrant County, he said, about 80 percent of Anglos vote Republican.

“The big change in Wendy Davis’ election was that the Anglos crossed over. Because there were so many more Anglos, she was elected on the basis of the Anglo crossover,” he said.

the rest of the story here.