WASHINGTON—Supreme Court justices wrestled Monday with the uncomfortable bargain struck between most victims of the opioid crisis and the Sackler family, whose Purdue Pharma promoted the addictive painkiller OxyContin: providing timely compensation for survivors in exchange for granting the wealthy family immunity from future civil lawsuits. 

That settlement was reached before a bankruptcy judge and approved in May by a federal appeals court in New York. It would see the Sacklers pay $6 billion to individual victims and state governments in exchange for eliminating potential liability for additional claims, such as fraud—even though they, unlike Purdue, haven’t sought bankruptcy protection. The deal was made under a catchall provision of federal law authorizing bankruptcy judges to issue orders and judgments that may be “necessary or appropriate” to resolve cases.