This factsheet authored by Bolder Advocacy provides examples of the kinds of advocacy activities that 501(c)(3) public charities and 501(c)(4) social welfare organizations are permitted to do under federal tax law. 501(c)(3)s are prohibited from supporting or opposing candidates for elected public office and must only engage in nonpartisan advocacy. On the other hand, 501(c)(4)s may engage in some partisan activity, but partisan political activity cannot be the primary purpose of a 501(c)(4) organization.