How Rhode Island Mostly -- and Perhaps Inadvertently -- Decriminalized Much Off-Street Prostitution in the Late 1970s:

An interesting article from the Providence Journal. As a federal district court ruled in 1980, "[T]he amendments appear to have decriminalized the sexual act itself, even when undertaken for remuneration. Thus, it appears to the Court that § 11-34-5 now outlaws only certain preliminary or preparatory activities (securing, transporting, receiving into a house or conveyance, etc.), and then only when pecuniary gain is somehow involved.

Thanks to How Appealing for the pointer.