High-stakes lawsuits accusing drugmakers, distributors, and pharmacies of stoking the national opioid scourge have suffered two major recent setbacks, and now it looks like plaintiffs could be headed for strike three. Only this time the problem may be less a controversial legal theory than a freelance Miss Marple on the jury. In Cleveland, the jury began deliberating Tuesday in a case pitting two Ohio counties against Walgreens, Walmart, and CVS pharmacies. The plaintiffs accuse the pharmacies of contributing to the opioid epidemic, asserting that the overall business of selling narcotic painkillers created a “public nuisance”—a prosecutorial approach that has run into growing judicial opposition because the sales involve legal products and services. Even if the jury finds for the plaintiffs and even if the problematic nuisance rationale can survive an appeal, there’s still the case of the rogue, unnamed juror reminiscent of Agatha Christie’s famous amateur detective. On a Friday …