Probable cause is defined as the right of a police officer to make an arrest, conduct a personal or property search, or to obtain a warrant for an arrest or a search. The term probable cause arose in the Fourth Amendment of the United States Constitution which defines the rights to freedom from unreasonable search and seizures without probable cause or a warrant. The Amendment reads like this:
"The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated, and no Warrants shall issue, but upon probable cause, supported by Oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized."
There are a couple of different definitions of probable cause that are used in the judicial system of the United States:
Probable cause can help to obtain arrest or search warrants, allow an officer to search or arrest a person, and allow an officer to seize the property of a person. If an officer does not have probable cause then he or she is not allowed to search or seize a person or a person's property without a warrant. Probable cause helps to protect not only the citizens of the United States but also law enforcement officials across the country from any legal action that can be taken if an unlawful search is conducted. An officer can be sued by a citizen of the United States if a search or seizure of body or property is performed without probable cause. The township or department that houses that officer can also be sued for wrongful search and seizure.
Probable cause can occur almost anywhere in the country at anytime. The majority of probable cause cases occur during traffic stops. If an officer notices anything in the vehicle that might be of danger to the officer or other people in the area, such as a weapon, then the officer is allowed to search the car without the consent of the person in the vehicle. Other items that can be searched for in the car with probable cause are drugs and alcohol or possible stolen goods.
Probable cause can be used by law enforcement officials in a variety of situations and places:
If an officer is dispatched to a residence or a place of work because of a disturbance, a domestic dispute, or any other emergency and the officer feels that there are weapons in the building or drugs in the building then they have probable cause to begin a search without a warrant or make an arrest without a warrant. These probable cause searches are legal in every state of the United States and can be upheld in a court of law.
Probable cause does cover public high schools, at least in New Jersey. A case that took place in 1985, New Jersey vs. T.L.O., set a precedent for searches of students and their lockers at public schools within the state. The case ruled that school officials act as state officers when conducting a search on the property. The catch is that in New Jersey, school officials do not require probable cause to search a student's property, only reasonable suspicion.
If probable cause leads to an arrest, it can sometimes be fought in court by a skilled criminal defense lawyer, leading to a lesser punishment, or a dismissal.