Today, the Supreme Court issued its much-anticipated opinion in Wal-Mart v. Dukes.

For those who like to skip ahead to the end to figure out whether their side won, the Court ruled in favor of Wal-Mart. That said, the real winner was the late Professor Richard Nagareda, whose articles on commonality clearly influenced Justice Scalia’s majority opinion.

In ruling for Wal-Mart, the Court issued two holdings: it held (5-4) that the plaintiffs had not met their burden on proving commonality, and (unanimously) that the plaintiffs could not certify a class for money damages under Rule 23(b)(2).

Now, what does the decision itself mean? Obviously, lawyers will be poring over the opinion in the coming months to tell us just that. But here are some highlights from the opinion.

Commonality means not common questions, but common answers.

Their claims must depend upon a common contention—for example, the assertion of discriminatory bias on the part of the same supervisor. That common contention, moreover, must be of such a nature that it is capable of classwide resolution—which means that determination of its truth or falsity will resolve an issue that is central to the validity of each one of the claims in one stroke.

The "rigorous inquiry" required for class certification is a factual inquiry.

Rule 23 does not set forth a mere pleading standard. A party seeking class certification must affirmatively demonstrate his compliance with the Rule—that is, he must be prepared to prove that there are in fact sufficiently numerous parties, common questions of law or fact, etc.

Plaintiffs must bring individualized monetary claims under Rule 23(b)(3).

[W]e think it clear that individ- ualized monetary claims belong in Rule 23(b)(3). The procedural protections attending the (b)(3) class— predominance, superiority, mandatory notice, and the right to opt out—are missing from (b)(2) not because the Rule considers them unnecessary, but because it considers them unnecessary to a (b)(2) class.

Statistical proof will not cure all problems with a proposed class.

The Court of Appeals believed that it was possible to replace such proceedings with Trial by Formula. A sample set of the class members would be selected, as to whom liability for sex discrimination and the backpay owing as a result would be determined in depositions supervised by a master. The percentage of claims determined to be valid would then be applied to the entire remaining class, and the number of (presumptively) valid claims thus derived would be multiplied by the average backpay award in the sample set to arrive at the entire class recovery—without further individualized proceedings. We disapprove that novel project. Because the Rules Enabling Act forbids interpreting Rule 23 to abridge, enlarge or modify any substantive right, a class cannot be certified on the premise that Wal-Mart will not be entitled to litigate its statutory defenses to individual claims.

(Internal citations omitted.)

And what does this mean for class-action litigation?

It means we’re likely to see more robust challenges to commonality at the certification stage. It also means that we’re likely to see fewer class actions pitched as seeking "injunctive relief" when what the plaintiffs (and their lawyers) really want is money damages. Combined with the Court’s other class-action decisions this term, it seems clear that the limits of the class action are more sharply defined, which defense attorneys can use to protect their clients from spurious class actions.