The defendant in a lawsuit must be served (delivered) a summons or citation (an order from the court to appear and answer the lawsuit) and a copy of the lawsuit (1) to provide due process (fairness) by giving the defendant notice of the lawsuit and the opportunity to appear in court and defend the lawsuit; and (2) to give the court personal jurisdiction (authority) over the defendant.
In Illinois, the process of serving a defendant with a summons and a copy of the lawsuit is a critical step in the legal process, as it ensures due process and establishes the court's personal jurisdiction over the defendant. Due process requires that the defendant is given proper notice of the lawsuit and the opportunity to appear in court to defend against the claims. This is accomplished by delivering the summons and complaint to the defendant in a manner prescribed by law. Illinois law allows for various methods of service, including personal delivery by a process server, service by certified mail, and in some cases, publication in a newspaper when the defendant cannot be located. Once served, the defendant has a specific number of days to respond to the lawsuit, typically 30 days. Failure to properly serve a defendant can result in delays or dismissal of the lawsuit. The rules governing service of process in Illinois are detailed in the Illinois Code of Civil Procedure.