If you read both the Breyer majority opinion and the mild dissent from Thomas, in light of (my analysis of) the previous "racial gerrymandering" cases (in Colorblind Injustice), Cromartie II isn't so difficult to understand, and SOC's silent consent to the majority opinion isn't, either.  Republican redistricters in 2001 will now be able to claim that by packing blacks and Latinos into as few districts as possible, and dispersing the rest in small numbers in safely Republican districts, they're acting for predominantly partisan reasons.  That should have been enough to convince the only member of the Supremes who's actually sat in a legislature during a redistricting, and the key to whose otherwise seemingly contradictory stances was Republican partisanship, to go along. 
   For Breyer, Ginsburg, Souter, and Stevens, this was just an opportunity to emphasize facts, rather than empty slogans, in a racial gerrymandering case, and to make it possible for redistricters of whatever political stripe in 2001 to deal with the most important schisms in politics with some degree of openness.
    Electoral lawyers should note, however, that neither opinion rejected Vera's "race as a proxy" language, which should assure your prosperity in the coming decade, because you can litigate either way.  Speaking of another team, potential expert witnesses may be in demand, for the Supremes may now pay closer attention to facts than they often did in the 90s -- when SOC used words like "segregated" and "Balkanized" to apply to 57% black districts -- and should be very careful, for the Supremes may analyze your every word.
    Historians of the racial gerrymandering decisions will wonder, however, just why SOC was convinced of the partisan purposes of the NC legislature in 1997, when the case for a predominant partisan intent was at least as strong in Shaw v. Hunt and Bush v. Vera.  My explanation is that by Cromartie II, she fully understood the partisan implications of giving Republicans the proper cue for the 2001 redistricting.
Morgan