A municipal ordinance of the city of Camden, New Jersey required that at least forty percent of the employees of contractors and subcontractors working on city construction projects be Camden residents. United Building & Construction Trades Council of Camden County (plaintiff) brought suit against the Mayor & Council of the City of Camden (defendants), challenging the ordinance on the grounds that it violated the Privileges and Immunities Clause of the Constitution. The New Jersey Supreme Court held that the dormant Commerce Clause did not apply to invalidate the ordinance because the city of Camden was acting as a market participant. The Privileges and Immunities Clause did not apply because the discrimination was based on municipal, not state residency. United Building appealed to the United States Supreme Court.