美国农业保护者协会,又称格兰其，其创办宗旨是倡导农场主互相协作，交流生产技术和科学知识，发展农村教育，以改善农场主状况。协会早期是一个不过问政治的农民互助团体，其影响力同样有限。随着美国第二次工业革命的推进，以铁路运输、仓储和机械生产商为代表的大资本家加强了对美国农民的盘剥，加之1873年经济萧条袭来，农场主的不满情绪日益高涨，他们纷纷加入格兰其以寻求帮助。从19世纪70年代初到80年代，格兰其从一个不干涉政治的农民社团迅速发展为参与联邦和地方政治行为的带有政党色彩的农民团体，协会影响力骤增，并一度取得不少成就。然而，随着美国经济的持续低迷，农场主要求采取更加激进的措施以应对紧缩的货币政策和不利的政治环境，而格兰其却坚持自身的保守特性，不愿过分的卷入政治活动，导致其成员大规模流失，影响力下降。此后格兰其不断地调整自身社会功能以避免自身衰败。随着进步主义运动的兴起，格兰其找到了调整的方向，即坚持自身非政党性，作为一种压力集团表达利益诉求，维持自身稳定发展。

The Patrons of Husbandry, known as Grange, whose purpose is proposing mutual working among farmers, communicating in technology and scientific knowledge, developing rural education and improving farmers’ situation. In its early stage, it is a society that keeps aloof from politics, with limited influence.With the advancement of the Second Industrial Revolution of America, American farmers were exploited by monopolist, represented by railway transport, storage and machinery makers, additionally, the Panic of 1873 made farmers even more dissatisfied, so they joined in Grange for support. From 1870s to 1880s, Grange led a farmer’s movement sweeping the whole country, in which its social function became even more radical: changed from a farmer’s association who took no interference in politics to a organization with partisanship and participated both in federal and local government. Its influence grew rapidly and achieved some accomplishments. However, as the economy continued being weak, the farmer required more radical measures to face the tightening of monetary policy and adverse political environment. While Grange insisted on its conservative features, and preferred not to involve into politics, thus its membership declined in large scale. Then Grange has been always adjusting its social function to avoid its disappearance. With the rise of the progressive movement, Grange found its direction of adjustment, which is insisting non-partisanship, but being a pressure group to express interest appeals, and maintain its stable development.