Supreme Court (Mark Wilson/Getty Images) Supreme Court (Mark Wilson/Getty Images)

The Supreme Court made one important ruling today, deciding unanimously that human genes cannot be patented. But with only a short time to go, the three biggest topics are still to come … not to mention that there’s still a potential surprise.

• Gay marriage: There are two cases on this one; the court needs to decide the status of marriage in California (Hollingsworth v. Perry), and also to decide whether the Federal Defense of Marriage Act is unconstitutional (Windsor v. U.S.). The tea-leaf readers expect at least partial good news for those who favor marriage equality, but all such predictions should be taken with several shakers full of salt.

• Affirmative action: Will the conservatives on the court fully eliminate affirmative action in Fisher v. University of Texas at Austin? Scale it back further? Leave it alone? That last one does not seem very likely.

• Voting Rights: In Shelby County v. Holder, the Court will rule on the key preclearance provisions of the Voting Rights Act — Section V. If they knock out Section V, it would be a major setback for the franchise.

There’s some speculation today about these cases based on which justices have written the fewest opinions so far during this term, with the conclusion that conservative justices are most likely to write most or all of these. Perhaps — but be careful. A majority including Justice Kennedy could make either liberals or conservatives happy. And remember that Chief Justice Roberts wound up with the liberals in his Affordable Care Act decision. The reality is that making predictions of what the court will do is a sucker’s bet; we really don’t know. Nor can we always even dope out the options; virtually no one on ACA predicted that the court would affirm most of the law but give the states an out on Medicaid expansion, something that will have enormous real-life consequences beginning next year.

Oh, and that surprise? Again, Court-based speculation doesn’t expect it, but it’s always possible that a justice will retire at the end of the term. If so, the showdown over nominations and the filibuster will go from huge to, well, I don’t know a big enough word to use. I’ve argued that Justice Ginsburg really should choose to retire now, if she wants to have the best chance of getting a replacement who cares about the issues she cares about. It may be unlikely that she’ll do it, but it’s certainly not impossible that she or another justice will make that decision.

All in all, as much as we focus on what Congress and the president are up to, the real action in June is likely to be from SCOTUS.