The main purpose of this legislation, known as the "Protecting Jobs in American Ports Act," is to allow passenger vessels that were not built in the United States to operate under U.S. coastwise laws. This change aims to enhance competition and potentially increase the availability of passenger services in U.S. waters. Key provisions of the law include a modification to existing regulations that govern coastwise endorsements for vessels. Specifically, it allows foreign-built passenger vessels to transport passengers between U.S. ports, either directly or through a foreign port.