Marriage equality is the hot-button topic at the Supreme Court this week, with the justices hearing two cases challenging the constitutionality of state and federal bans on same sex marriage.

Yet that's not the only thorny issue the justices will tackle this year. Two other cases address another lightning rod topic: Affirmative action.

In a surprise decision, the Supreme Court on Monday announced that it would hear an affirmative action case out of Michigan — even though the court has yet to rule on a separate case addressing affirmative action at the University of Texas. That the court would hear two cases on the same issue in quick succession has observers wondering if they're preparing to deliver a pair of rulings that, combined, would have a wide-reaching impact.

The justices have already heard oral arguments for the Texas case, and should already know the scope of their coming ruling. If they were prepared to issue a broad ruling for or against affirmative action there, "it would seem to be unnecessary to hear the Michigan case," notes NPR's Nina Totenberg.

From ProPublica's Nikole Hannah-Jones:

The court's move surprised activists on both sides of the affirmative action issue, who then quickly did the analysis: Instead of a sweeping ruling on affirmative action, the Texas case may be decided more narrowly. In taking another case right on its heels, the activists believe, the court might well have opted to undo the fabric of race-conscious laws and policies thread by thread. [ProPublica]

In addition, the Michigan case is "significantly broader" than Texas', says SCOTUSblog's Lyle Denniston, since it involves a statewide constitutional ban on affirmative action. The case, Schuette v. Michigan Coalition to Defend Affirmative Action, stems from a 2006 ballot initiative that amended the state constitution to ban race-based considerations for higher education and public employment. Voters passed that measure by a 58-42 vote, but an appeals court in November struck down the parts of the law addressing higher education, saying they discriminated against minorities and violated the 14th Amendment.

In contrast, the Texas case, Fisher v. University of Texas, addresses a single school's use of race-conscious admittance criteria. In that case, a white student who was denied admission sued the school, challenging whether the university could legally consider race when attempting to build a diverse student body.

Though a larger ruling on the legality of affirmative action could be extrapolated from that case, Michigan's affirmative action ban presents a more clear-cut path to issuing a broad decree.

From SCOTUSblog's Denniston:

The Fisher case, while it does have fairly broad potential, focuses directly only on the specifics of an affirmative action plan at Texas’s flagship university in Austin, and so the ruling in that case might not go much beyond that plan. The Michigan case, however, involves a move by a state to deny its public colleges and universities any right to use race as a factor in choosing the incoming class of students. It thus has the potential to produce a far more sweeping decision. [SCOTUSblog]

The Supreme Court is expected to rule on the Texas case as early as this week. The Michigan case won't be heard until at least October, when the court's next session kicks off, with a ruling probably coming in 2014.

The two cases come to the court ten years after it upheld an affirmative action program at the University of Michigan in a 5-4 decision. But since then, Justice Sandra Day O'Connor, who wrote the majority opinion in that case, has been replaced by the more conservative Justice Samuel Alito, making a sharp reversal on the issue a real possibility.