by Michael Barone
...In the other big states mentioned above Republicans concentrated on bolstering current incumbents rather than creating new districts. Big Hispanic population increases in Texas and Florida forced Republicans to create new Democratic districts.
Another reason for Republicans' limited success is that Democrats successfully gamed the supposedly nonpartisan redistricting commissions in California and Arizona. Democrats will likely gain one seat in Arizona and two in California, even though for the first time in history that state gained no seats through reapportionment.
A third reason is the effect of the prevailing interpretation of the Voting Rights Act. Republicans have been helped by its insistence on the creation of black-majority districts. That crams heavily Democratic precincts into a few districts, leaving Republicans a better shot at districts next door.
But the law also insists on Hispanic-majority districts, although few Hispanics have ancestors subject to discrimination in this country and although many are non-citizens ineligible to vote. In Texas, where Hispanics are less Democratic than elsewhere, Republican redistricters adjusted by creating several elongated districts linking Hispanic-majority areas with heavily Republican counties.
All these results tend to refute some conventional wisdom about redistricting.