In nations with a federal government, such as Australia, Mexico, the United States, and Venezuela, among others, a federal warrant is a legal document issued by a federal judge which allows people to conduct a search, seizure, or arrest. Federal warrants are executed by members of the federal government or authorized representatives; for example, in the United States, if a Highway Patrol officer pulls someone over and that person has an outstanding federal warrant, the officer is allowed to make an arrest.
In order for a federal warrant to be granted, a government representative must demonstrate before a federal judge or magistrate that there is cause to support the warrant. Reasons to issue a federal warrant can include a federal indictment, which can result in the issuance of a federal arrest warrant, or probable cause on the basis of an ongoing investigation which indicates that a search can be legally conducted, in which case a federal search warrant will be issued. Federal warrants for asset seizure can be issued in cases such as tax evasion and crimes which mandate seizure and holding of assets.
The terms of the federal warrant must be clearly defined under the rules of law and procedure. A search warrant, for example, would give the address or location for the search and indicate whether the warrant covered the whole area, or a specific location. Likewise, a warrant to seize assets would define which assets were subject to seizure. These measures are designed to protect people from unreasonable search and seizure. Failure to follow the warrant carefully can result in problems with evidence at trial.
Federal law enforcement officers are usually the ones to request a federal warrant. The judge weighs the information presented to determine whether or not the warrant complies with the rule of law. Judges can choose to deny a request for a warrant if they feel that it is not reasonable or that the cause for the warrant has not been fully demonstrated. If a judge feels that the products of a search are likely to be challenged in court, for example, the warrant will not be granted and the person requesting the warrant will be asked to muster more supporting information.