In civil litigation, most lawsuits are resolved by the voluntary agreement (settlement) of the parties (litigants) before the judge, jury, or arbitrator decides how the case should be resolved. But if a case goes to trial and the judge or jury decides how the case should be resolved, one or more parties to the lawsuit may appeal that decision to a higher court—usually a court of appeals, whether in the state court system or the federal court system.

And one or more of the parties who are dissatisfied with the decision of the court of appeals generally may ask the highest court in the jurisdiction (state court or federal court) to review the decision of the lower court(s). The highest court in the state court system is often called the supreme court—but in some states it has a different name—for example, in New York it is called the New York Court of Appeals. And in the federal court system the highest court is the United States Supreme Court.

There are different standards by which higher courts review the decisions of lower courts, and these are known as standards of review. In many cases appellate courts are required to give deference to the decision made by the jury or the lower court. These decisions are reviewed for an abuse of discretion, and the higher court will only reverse the lower court’s decision if it determines the lower court abused its discretion. And in some states certain decisions made by the lower court or the jury are reviewed using a substantial evidence standard, and the question for the higher court is whether there is substantial evidence to support the decision of the lower court or the jury. Finally, some decisions are reviewed without giving deference to the decision made by the jury or the lower court, and this standard of review is called de novo review.

Similarly, in criminal prosecutions, the prosecution (state or federal government) or the defendant (person or entity) may generally appeal the decision of the jury or judge to the intermediate appellate court (often the court of appeals), and ultimately to the highest court (often the state supreme court, or the U.S. Supreme Court, or other court of last resort).

In Montana, as in other states, civil litigation often concludes with a settlement between the parties before a case reaches a verdict by a judge or jury. However, if a case does go to trial and a decision is rendered, the losing party has the right to appeal to a higher court. In Montana, the first level of appeal would typically be to the Montana Supreme Court, as the state does not have an intermediate appellate court. The Montana Supreme Court is the highest court in the state's judiciary system. If a party is still dissatisfied with the outcome after the state supreme court's decision, they may petition for the United States Supreme Court to review the case, although the U.S. Supreme Court has discretion over whether to take the case. The standards of review used by appellate courts in Montana include 'abuse of discretion' for decisions that are reviewed with deference to the lower court, 'substantial evidence' for factual determinations, and 'de novo' for issues of law where no deference is given to the lower court's decision. These standards determine how closely the appellate court will scrutinize the lower court's decision. In criminal cases, both the prosecution and the defense have similar rights to appeal decisions to higher courts, following the same general principles and standards of review.