I have little profound to say about this, especially since I haven't yet had time to read the opinions, but it appears that Anthony Kennedy's federalist persona was in the ascendancy the other day when SCOTUS ruled that the Michigan Civil Rights Initiative (passed by those "foolish masses" of democratic voters back in 2006) is indeed constitutional. That this should even have been in question gives one just a glimpse into the mad, mad world of what passes for constitutional jurisprudence in this country. See my discussion from two years ago of the "reasoning" that lay behind considering it unconstitutional.
I haven't had time to sort it all out, but here is a discussion (to be sure, a biased discussion, but still informative) of the "political process doctrine." Evidently Scalia and Thomas held that those earlier precedents enshrining the political process doctrine should be overturned. Naturally, Ginsberg and Sotomayer wanted the MCRI overturned on the basis of those same precedents.
A head-spinning irony (evident in the above explanatory article from Gawker) is that one of the earlier precedents (Hunter, 1969) involved a situation where state voters had made it harder for cities to pass racial non-discrimination laws. The Supreme Court held that this was unconstitutional. In the Hunter case what SCOTUS was trying to do was to promote the passage of laws against discrimination, whereas the minority in the MCRI case was using that same precedent to try to make it impossible for a state to put a real, even-handed, non-discrimination law into its state constitution. Say, what? Of course, we all know how this happens: It's all driven by results. SCOTUS in Hunter was against the voters because the voters were trying to block future city laws that, SCOTUS believed, would be good (if passed) for the mascot group they favored. In Schuette, the court minority is upset because the citizens of Michigan, by passing a real non-discrimination law at the state level, have banned affirmative action programs that, the court believes, will be good for the mascot groups they favor! So if anti-discrimination laws are expected to be good for the mascot group, it is "unconstitutional" to make it harder to pass them. If an anti-discrimination law at the state level is expected to be bad for the favored mascot group (by preventing reverse discrimination), then it is "unconstitutional" to pass it. Get that? Yeah, we get it. It's all about results. And this is legal reasoning? Well, apparently in Hunter and in Seattle (a 1982 case in which SCOTUS struck down an anti-busing ballot measure), that is indeed what passes for legal reasoning. Good for Scalia and Thomas for saying they should be overturned. Evidently others in the majority thought they could thread the needle, so I suppose technically they aren't overturned. But it's rather pleasant to listen to the weeping and wailing on the left, where this is definitely seen as a blow against their dubious political process doctrine.
In case you've read that the decision was 6-2 and notice that that adds up only to eight, Kagan recused herself.
By the way, little is being said about this in the news, but the MCRI also forbade affirmative action on the basis of gender. Since, if anything, gender discrimination (in favor of females) comes up even more often in higher education than affirmative action on the basis of race, I hope all those "diversity committed" public university administrators in the State of Michigan were awake and noticing this little victory for common sense.