A grassroots movement (often referenced in the context of a political movement) is one which uses the people in a given district as the basis for a political or economic movement. Grassroots movements and organizations use collective action from the local level to effect change at the local, regional, national, or international level. Grassroots movements are associated with bottom-up, rather than top-down decision making, and are sometimes considered more natural or spontaneous than more traditional power structures. Grassroots movements, using self-organization, encourages community members to contribute by taking responsibility and action for their community. Grassroots movements utilize a variety of strategies from fundraising and registering voters, to simply encouraging political conversation. Goals of specific movements vary, but the movements are consistent in their focus on increasing mass participation in politics. These political movements may begin as small and at the local level, but grassroots politics as Cornel West contends are necessary in shaping progressive politics as they bring public attention to regional political concerns
The idea of grassroots is often conflated with participatory democracy. The Port Huron Statement, a manifesto seeking a more democratic society, says that to create a more equitable society, "the grass roots of American Society" need to be the basis of civil rights and economic reform movements. The terms can be distinguished in that grassroots often refers to a specific movement or organization, whereas participatory democracy refers to the larger system of governance. The Green Party of the United states is a major Grass roots movement. It is a political party, for the people, by the people.
The earliest origins of the use of "grass roots" as a political metaphor are obscure. In the United States, an early use of the phrase "grassroots and boots" was thought to have been coined by Senator Albert Jeremiah Beveridge of Indiana, who said of the Progressive Party in 1912, "This party has come from the grass roots. It has grown from the soil of people's hard necessities".
In a 1907 newspaper article about Ed Perry, vice-chairman of the Oklahoma state committee, the phrase was used as follows: "In regard to his political views Mr. Perry has issued the following terse platform: 'I am for a square deal, grass root representation, for keeping close to the people, against ring rule and for fair treatment.'" A 1904 news article on a campaign for possible Theodore Roosevelt running mate Eli Torrance quotes a Kansas political organizer as saying: "Roosevelt and Torrance clubs will be organized in every locality. We will begin at the grass roots".