These flags were first used in World War I, with subsequent standardization and codification by the end of World War II. They were not popular during the Vietnam War, but have come back into use. In modern usage, an organization may fly a service flag if one of its members is serving active duty. On April 21, 2010 the United States House of Representatives passed House Resolution 855, a stand alone resolution recognizing the Silver Star Service Banner and making May 1 Silver Star Service Banner Day. One state, Missouri, took steps to make such recognition a state law.