As treaties decline, customary international law can be an important mechanism of international cooperation over the medium term. There are increasingly fewer treaties ratified by the United States, with a record-low number of five in 2009–2012, and fewer multilateral treaties adopted worldwide. Yet, the demand for global rules and standards has not abated. Thus, for many international questions where treaties are not available as a source of new rules, customary international law may serve as an interchangeable instrument of national policy.