Let's take a step back: Texas' legislature drew a new map to account for the decennial census, population growth, etc. Because Texas is a covered jurisdiction under Section 5 the Voting Rights Act of 1965, it had to submit its map to the United States District Court for the District of Columbia or the Department of Justice for "preclearance"—i.e., to ensure that minorities weren't screwed over. They chose the Court. That's still ongoing.
In the meantime, plaintiffs sued Texas in the United States District Court for the Western District of Texas alleging that the map, in fact, discriminated against Latinos and African-Americans and diluted their voting strength, notwithstanding the fact that Latinos and African-Americans accounted for three-quarters of Texas’ population growth since 2000. Sensing some merit in the plaintiffs' claims and fearing that the DC court wouldn't complete its process in time, the Texas court drew its own map—since Texas has an early primary and wants to have something firmly in place by February 1. And that, writes the Court today in a per curiam (i.e., unsigned) opinion), is where it screwed up:
[H]ere the scale of Texas’ population growth appears to require sweeping changes to the State’s current districts. In areas where population shifts are so large that no semblance of the existing plan’s district lines can be used, that plan offers little guidance to a court drawing an interim map. The problem is perhaps most obvious in adding new congressional districts: The old plan gives no suggestion as to where those new districts should be placed. In addition, experience has shown the difficulty of defining neutral legal principles in this area, for redistricting ordinarily involves criteria and standards that have been weighed and evaluated by the elected branches in theSo fix it if you must, but don't start from scratch:
exercise of their political judgment. Thus, if the old state districts were the only source to which a district court could look, it would be forced to make the sort of policy judgments for which courts are, at best, ill suited.
To avoid being compelled to make such otherwise standardless decisions, a district court should take guidance from the State’s recently enacted plan in drafting an interim plan. That plan reflects the State’s policy judgments on where to place new districts and how to shift existing ones in response to massive population growth. This Court has observed before that “faced with the necessity of drawing district lines by judicial order, a court, as a general rule, should be guided by the legislative policies underlying” a state plan—even one that was itself unenforceable—“to the extent those policies do not lead to violations of the Constitution or the Voting Rights Act.”
[T]he state plan serves as a starting point for the district court. It provides important guidance that helps ensure that the district court appropriately confines itself to drawing interim maps that comply with the Constitution and the Voting Rights Act, without displacing legitimate state policy judgments with the court’s own preferences.The Supremes thus sent the judges to the drawing board—literally!—to try again, a compromise advanced by Justice Kagan during oral argument.
(Justice Thomas concurred separately to again remind everyone that he regards this whole "preclearance" business to be unconstitutional.)
What does this mean politically? In short, explains Rick Hasen, a map that's more deferential to Texas' original map will be more favorable to Republican political objectives. Indeed, here's what our Steve Singiser said when the judge-drawn map was released:
With this morning's unveiling of the court-approved interim Congressional maps, one thing became clear immediately: Republican overreach on their attempt to remap the Lone Star State has cost them, at a minimum, two Congressional seats, and perhaps more.Sadly, that's less thinkable now.
Whereas Barack Obama only carried 10 of the 36 seats under the GOP map that was rejected earlier this year, the president won a majority of the vote in 13 of the seats in the new court-approved map, as you can see in this comparison spreadsheet.
[Many, many details.]
The bottom line is that, assuming the districts are not dramatically altered before the final map gets released, a state that looked like a net loss of two seats for the Democrats now looks no worse (absent a total national collapse for the blue team) than a net gain of two. Indeed, unless a huge alteration or a lawsuit changes the calculus here, the only remaining question would appear to be how many seats the Democrats will pick up in Texas, an outcome that seemed unthinkable at the start of the year.