Soft law consists of rules issued by lawmaking bodies that do not comply with procedural formalities necessary to give the rules legal status yet nonetheless influence the behavior of other lawmaking bodies and of the public. Soft law has been much discussed in the literatures on international law, constitutional law, and administrative law, yet congressional soft-lawmaking, such as the congressional resolution, has received little attention. Congressional soft law affects behavior by informing the public and political institutions about the intentions and policy preferences of Congress, which are informative about future hard law as well as of Congress's view of the world, and thus relevant to the decision making of various political agents as well as that of the public. Congressional soft law is important for a range of topics, including statutory interpretation and constitutional development. Other types of soft law—international, constitutional, and judicial—are compared.