In the United States, the ability to appeal a case after a higher court renders a favorable opinion depends on the specific circumstances of the case and the stage of the legal proceedings. Generally speaking, parties who have lost a case at the trial level may appeal the decision to a higher court, and if the higher court issues a favorable opinion, the case may be remanded back to the trial court for further proceedings. However, once a case has been fully resolved and all appeals have been exhausted, it is generally not possible to re-open the case based on a change in the law or a new legal standard.
In the case of Monasky v. Taglieri, if the parties who lost previous cases can demonstrate that the standards applied in their cases were in error and that the new standard established by the Supreme Court would have resulted in a different outcome, they may be able to appeal their cases. The specific process for doing so would depend on the state and federal court system involved, but generally it would require a motion for a new trial or a writ of habeas corpus.
The time window for such appeals is also determined by the jurisdiction and the court system involved. In most cases, parties have a limited time period in which to file an appeal, known as the statute of limitations. The time limits for filing an appeal can vary depending on the type of case and the court that heard the case.