What is the fourth?

Answer 1

The Fourth amendment to the ConstitutionAmendment 4 - Search and Seizure. Ratified 12/15/1791.

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.

No unreasonable searches can be made unless they have a warrant or a written statement saying they can do the search in the house

The fourth amendment of the Constitution is part of the Bill of Rights and basically guards against unreasonable searches and seizures. It's the reason people on like CSI can't go inside someone's house or search their car without a warrant. Unless the police have probable cause against you, they cannot search or arrest you without a warrant.
The amendment specifically requires search and arrest warrants be judicially sanctioned and supported by probably cause. It was adopted as a response to the abuse of the writ of assistance, which is a type of general search warrant, in the American revolution. Search and arrest should be limited in scope according to specific information supplied to the issuing court, usually by a law enforcement officer, who has sworn by it.
Protects Americans "against unreasonable searches and seizures"
The fouth amendement states that we the citizens should protect individuals against unreasanble searches and seizures
The fourth amendment protects citizens from unreasonable searches and seizures (a legal procedure where, if the police or other authorities suspect a crime has been committed, they can search a person's property to get evidence). In addition, it also requires search and arrest warrants to be judicially sanctioned and supported by probable cause (the standard by which officers have the grounds to arrest someone).
George Washington
The 4th Amendment was important back then, because the British had the right to invade colonists homes and seize and/or charge the person with crime. The founding fathers wanted to protect the citizens in the future. This is important now because people can go on with their daily lives w/o the fear of government interfering. (: