Are brief investigatory stops by law enforcement officers immune to the fourth amendment?

Brief investigatory stops by law enforcement officers, such as occurred here, are not immune from the strictures of the fourth amendment. See United States v. Cortez, 449 U.S. 411, 417 (1981). "An investigatory stop must be justified by some objective manifestation that the person stopped is, or is about to be, engaged in criminal activity." Id. (footnote omitted). While this determination is based upon the totality of the circumstances, the officer's conclusion must "raise a suspicion that the particular individual being stopped is engaged in wrongdoing." Id. at 418 (emphasis added).