Personal jurisdiction is a court’s jurisdiction over the parties, as determined by the facts in evidence, which bind the parties to a lawsuit, as opposed to subject-matter jurisdiction, which is jurisdiction over the law involved in the suit. Without personal jurisdiction over a party, a court’s rulings or decrees cannot be enforced upon that party, except by comity; i.e., to the extent that the sovereign which has jurisdiction over the party allows the court to enforce them upon that party. A court that has personal jurisdiction has both the authority to rule on the law and facts of a suit and the power to enforce its decision upon a party to the suit. In some cases, territorial jurisdiction may also constrain a court’s reach, such as preventing hearing of a case concerning events occurring on foreign territory between two citizens of the home jurisdiction. A similar principle is that of standing or locus standi, which is the ability of a party to demonstrate to the court sufficient connection to and harm from the law or action challenged to support that party’s participation in the case.