The First Amendment of the United States Constitution specifically allows peaceful demonstrations and the freedom of assembly as part of a measure to facilitate the redress of such grievances. Demonstrations can be used to show a viewpoint (either positive or negative) regarding a public issue, especially relating to a perceived grievance or social injustice. A demonstration is usually considered more successful if more people participate. Topics of demonstrations often deal with political, economic, and social issues. Photograph originally captioned: Derby-hatted throng at Boston labor demonstration, 1910's.