Yes, 501(c)(3) nonprofit organizations may support or oppose legislation relevant to their mission within certain limits. However, 501(c)(3) nonprofit organizations are prohibited from political campaign activity--they may not support or oppose candidates for elective office. A 1976 law by Congress under which charities may elect to operate sets limits on the amount of legislating lobbying by 501(c)(3) organizations, up to 5% or in some cases as much as 20% of organization expenditures, in order to ensure that policy makers can be informed by what charities learn about the people and communities they serve. For more information about charity lobbying in the public interest, visit the web site of Independent Sector or call them at (202) 223-8100.  The Mississippi Center for Nonprofits can also provide custom training in this area. http://www.independentsector.org/