North American Bioregional Assemblies have been bi-annual gatherings of bioregionalists throughout North America since 1984 and have given rise to national level Green Parties. In addition, bioregionalism spawned the sustainability movement. The tenets of bioregionalism are often used by green movements, which oppose political organizations whose boundaries conform to existing electoral districts. This problem is perceived to result in elected representatives voting in accordance with their constituents, some of whom may live outside a defined bioregion, and may run counter to the well-being of the bioregion.