The Declaration of the Causes and Necessity of Taking Up Arms (more formally, A Declaration by the Representatives of the United Colonies of North-America, Now Met in Congress at Philadelphia, Setting Forth the Causes and Necessity of Their Taking Up Arms), issued by the Second Continental Congress on July 6, 1775, explained why the American colonies were girding themselves for war with Great Britain—the war that would become the American Revolutionary War. Its author was Pennsylvania delegate John Dickinson, although Dickinson’s final draft was based in large part on an earlier draft written by Thomas Jefferson.