It might be that population-based redistricting in Texas, and for that matter in most states, is unwise for this reason. The argument that these practices are quite administrable and wholly consistent with decades of practice, while true, may not end up being the decisive one. The Court has, for once, largely left this matter to the political process to decide. But the plaintiffs have lost this political battle in Texas, so they now seek to read a newer, narrow theory of political representation into the Constitution, a stage beyond what even the Warren Court felt comfortable doing—creating an ever-more uniform political theory derived under a construction of the words “the equal protection of the laws.”
Texas, along with the other 49 states, has remained free to adopt one of several theories of representative government within the confines of Reynolds v. Sims. But Evenwel threatens not only to deprive the states of their authority to do so, but also to impose a standard that is squarely at odds with the structural design of the Constitution: representative government includes representation of all persons, not simply voters.
And one can hope that the Court will leave the development of additional political theory to the political branches.
I raised similar concerns about Evenwel, from a different political perspective, over at Slate.