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.

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: