For starters, the term “jurisdiction” in the United States can refer to either subject-matter jurisdiction or personal jurisdiction. Subject matter jurisdiction means the type of case a court can decide.
Personal jurisdiction refers to a court’s power over a person – – here meaning a natural person (human being), or a legal person (a business). Long arm jurisdiction is one type of personal jurisdiction.
In practice, personal jurisdiction is all about whether a court has power over a defendant. Can the court force the defendant to come to court? If the court doesn’t have personal jurisdiction over a person, the court has no power to issue a judgment against that person.
Long Arm Jurisdiction
One issue that courts in the United States must consider is whether a court located in one state can assert personal jurisdiction over a defendant in another state. Every state has a law called a long-arm statute which authorizes the state to assert jurisdiction over an out-of-state defendant under certain circumstances. For example, let’s say a plaintiff from New York wants to sue a defendant who is a resident of New Jersey. If the plaintiff sues in a court located in New York, the plaintiff will have to ask the court to assert long arm jurisdiction over the New Jersey defendant.
Below is a video (updated) on long-arm jurisdiction: