Is the Flint water crisis a local calamity or a national controversy with far-reaching implications?

The answer, already subject to two rounds of appellate jockeying before the U.S. Court of Appeals for the Sixth Circuit, could ordain who has the upper hand in dozens of class actions against public officials and engineering firms stemming from the discovery of tainted drinking water in Flint, Michigan.

From the start, the cases faced numerous hurdles. But so far, they've been mired in jurisdictional battles that test the “local controversy” exception to the Class Action Fairness Act. The 2005 law, known as CAFA, expanded federal jurisdiction for class actions and made it easier for defendants to remove cases to federal court.