In Skinner v. Railway Labor Executives' Assn., 489 U.S. 602 (1989), the court, after recognizing the need to balance the relevant interests, found:
"In most criminal cases, we strike this balance in favor of the procedures described by the Warrant Clause of the Fourth Amendment.
Except in certain well-defined circumstances, a search or seizure in such a case is not reasonable unless it is accomplished pursuant to a judicial warrant issued upon probable cause.
We have recognized exceptions to this rule, however, 'when "special needs, beyond the normal need for law enforcement, make the warrant and probable-cause requirement impracticable." '
When faced with such special needs, we have not hesitated to balance the governmental and privacy interests to assess the practicality of the warrant and probable-cause requirements in the particular context."
The "special needs" exception was again recognized by the Supreme Court in Treasury Employees v. Von Raab (1989) 489 U.S. 656, 665-666 [109 S. Ct. 1384, 1390-1391, 103 L. Ed. 2d 685]:
"Our cases establish that where a Fourth Amendment intrusion serves special governmental needs, beyond the normal need for law enforcement, it is necessary to balance the individual's privacy expectations against the Government's interests to determine whether it is impractical to require a warrant or some level of individualized suspicion in the particular context."