A lesbian couple known only by their initials lived together in Hoover, Alabama, from 1995 until 2011. During that time, E.L. had three children through “assisted reproductive technology.” That meant E.L. was the legal parent under Alabama law; V.L. was not. In 2006, they temporarily moved to Georgia, where a state court permitted V.L., with E.L.’s consent, to become an adopted parent to the children. They then returned to Alabama.

By 2011, however, the couple split up. E.L. kept the children, and V.L. filed suit in an Alabama court asking for visitation rights, citing the Georgia adoption. E.L. fought back by arguing a variety of points, including that the Georgia same-sex adoption violated Alabama’s “public policy” (a code phrase for its constitutional amendment specifying that any “union replicating marriage of or between persons of the same sex . . . in any other jurisdiction shall be considered and treated in all respects as having no legal force or effect in this state”). Two lower courts rejected that argument; but the state supreme court issued a tricky ruling. It did not address the validity of same-sex families; instead, it held that Alabama courts were not obligated to respect the Georgia adoption.

This is usually a pretty big no-no under Article IV of the U.S. Constitution, which provides that “[f]ull faith and credit shall be given in each state to the public acts, records, and judicial proceedings of every other state.” A divorce, or an adoption, or any other judicial act in State A is almost always binding on State B. It’s something that the courts have felt pretty strongly about since roughly 1789. The only real exception would be if the first state court had no “jurisdiction” over the case.

“Jurisdiction” stems from the Latin words for “saying the law.” A court must have the power to “say the law” in any given case—by which is meant that it must have legal power, first, over the parties to the case (“personal jurisdiction”) and, second, over the kind of case (“subject-matter jurisdiction”).

I may want to sue my next-door neighbor in federal court for, let’s say, violation of Paraguayan intellectual-property law. The U.S. federal court won’t have subject matter jurisdiction, because (1) no statute puts it in charge of matters Paraguayan and (2) the parties are both citizens of the District of Columbia, meaning there’s no “diversity.” Fine. I jet off to Asunción and file suit in Paraguayan civil court. That court would have subject-matter jurisdiction, meaning it could hear the case; but it wouldn’t have personal jurisdiction over my neighbor; Paraguayan courts have no power to issue a summons to someone in D.C.

In V.L. v. E.L., the Alabama court engaged in some fancy footwork to determine that the Georgia court never could have heard the case. The argument went like this: Under Georgia law, the Georgia court was supposed to obtain a formal surrender of parental rights from E.L. before allowing V.L. to adopt; it didn’t (because E.L. was asking it to allow the adoption, and anyway Georgia law is unclear). Because it was supposed to get the surrender first, the adoption was invalid.