U.S. citizenship is a legal status that grants individuals the rights and privileges associated with being a member of the United States, including the right to vote, work, and reside in the country without restriction. This status can be acquired either by birth within U.S. territory, through U.S. citizen parents, or via the naturalization process for immigrants. The implications of U.S. citizenship were particularly significant following events like the Spanish-American War, which led to territorial expansions and raised questions about the citizenship status of newly acquired populations.