As class certification wanes, plaintiffs’ lawyers resolve hundreds of thousands of individual lawsuits through aggregate settlements in multidistrict litigation. But without class actions, formal rules are scarce and judges rarely scrutinize the private agreements that result. Meanwhile, the...

Federal courts routinely need to apply state law, but this task becomes complicated when no definitive state law exists. In these instances, federal judges have a few options, including making an Erie guess, or certifying the question of state law to the highest state court. During the U.S....