489 U.S. 656 109 S.Ct. 1384 103 L.Ed.2d 685 NATIONAL TREASURY EMPLOYEES UNION, et al., Petitionersv.William VON RAAB, Commissioner, United States Customs Service. No. 86-1879. Argued Nov. 2, 1988. Decided March 21, 1989. Syllabus The United States Customs Service, which has as its primary enforcement mission the interdiction and seizure of illegal drugs smuggled into […]