The Supreme Court refused to hear a case involving the question of whether a Colorado law requiring remote sellers to inform Colorado purchasers annually of their purchases and send the same information to the Colorado Department of Revenue is unconstitutional. As is always the case, the Supreme Court gave no reason for denying the petition.
In Quill Corp. v. North Dakota, decided in 1992, the Supreme Court held that states cannot require retailers with no in-state physical presence to collect sales tax. In 2010 the Colorado legislature passed the law described above to improve sales tax collection. The Direct Marketing Association sued Colorado claiming the law unconstitutionally discriminates against interstate commerce and is unconstitutional under Quill.