The Fourth Amendments has two main clauses: a rights clause and a prohibition on certain types of warrants clause (the prohibition clause):

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.

Significantly, the two clauses are separated by an “and.”  This “and” has led to an uncertainty about the relationship between the two clauses. Some people argue that searches and seizures without warrants are unreasonable, except in limited circumstances.  Others argue that searches and seizures do not require warrants under any circumstances.  Instead such warrants were used as a defense by government officials against tort claims for illegal searches and therefore were restricted to certain situations.

Interestingly, the original version of the Fourth Amendment did not have this structure.  James Madison’s proposed version of what would become the Fourth Amendment provided:

The rights of the people to be secured in their persons; their houses, their papers, and their other property, from all unreasonable searches and seizures, shall not be violated by warrants issued without probable cause, supported by oath or affirmation, or not particularly describing the places to be searched, or the persons or things to be seized.

Madison’s provision only provides protection from certain kinds of warrants – the protection provided by the prohibition clause.  While it includes the language of the rights clause, this language does not confer that right independently.  Instead, Madison’s provision merely states that the right can be violated by violating the prohibition clause.  In fact, the rights clause narrows the scope of the prohibition clause by limiting it to “persons, houses, papers, and other property.”

One possibility for Madison’s provision was that it sought to work a compromise between two views of the right at issue.  The Massachusetts Constitution of 1780 provided for both the rights clause and the prohibition clause: “Every subject has a right to be secure from all unreasonable searches, and seizures of his person, his houses, his papers, and all his possessions. All warrants, therefore, are contrary to this right” if they do not satisfy the various requirements in the prohibition clause.

By contrast, the Virginia Declaration of Rights provided only for the prohibition clause.  Madison, a Virginian, might have sought to work a compromise, which would have operated much like the Virginia Declaration.  Instead, the Amendment was changed to follow the Massachusetts provision.