The Green Party of the United States (GPUS) is a national American political party founded in 1991 as a voluntary association of state green parties. With its founding, the Green Party of the United States became the primary national Green organization in the United States, eclipsing the Greens/Green Party USA, which emphasized non-electoral movement building. The Association of State Green Parties (ASGP), a forerunner organization, first gained widespread public attention during Ralph Nader's United States presidential campaigns in 1996 and 2000.
The Green Party in the United States has won elected office at the local level; most winners of public office in the United States who are considered Greens have won nonpartisan elections. The highest-ranking Greens ever elected in the nation were: John Eder, a member of the Maine House of Representatives until his defeat in November 2006; Audie Bock, elected to the California State Assembly in 1999 but switched her registration to Independent seven months later running as an independent in the 2000 election; and Richard Carroll, elected to the Arkansas House of Representatives in 2008 but switched parties to become a Democrat five months after his election. In 2005, the Green Party had 305,000 registered members in states allowing party registration, and tens of thousands of members and contributors in the rest of the country.