In a civil lawsuit, when one party seeks an official court order for something, they must first file a motion explaining to the court what they want done and what the legal basis is for the request. In most cases, the opposing party is allowed a formal opportunity to respond to the motion in writing and/or at a hearing. A motion for preliminary injunction is a motion filed while a lawsuit is pending asking the court to prevent the other party from doing something or forcing the other party to maintain the status quo until the court actually decides the merits of the case.
The requirements for filing a motion for preliminary injunction will differ among jurisdictions. Within the United States, state courts may make their own rules and procedural requirements for the filing of a motion for preliminary injunction. As a rule, however, the party requesting a preliminary injunction must show the court four things: that there is a substantial liklihood that the party requesting the injunction will win on the merits of the case; that the harm balanced in granting the injunction outweighs the harm balanced in denying the injunction; that there is a substantial threat of irreparable harm could occur without the injunction; and that the interest of the public is best served by granting the injunction.
A motion for preliminary injunction is something that a court is reluctant to grant as it amounts to making a preliminary decision on the merits of a case prior to all the facts and evidence being admitted. For this reason, a party seeking an injunction has an uphill battle in most cases. The motion should be accompanied by as much factual information and documentary evidence as possible in order to give the court a legal basis for granting the motion.
Typically, the court will give the opposing party a chance to respond to the motion for preliminary injunction; however, the time frame for responding is normally expedited. Rules of civil procedure frequently allow a party as much as 30 days to respond to a motion filed with the court. In the case of a preliminary injunction, the opposing party may have only a few days or as little as a few hours to respond depending on the subject of the injunction. If the court finds in favor of the requesting party, the injunction will remain in place until further order of the court or until the case is decided on the merits.