The basic tenet is 501(c)(3) organizations have a strict prohibition against lobbying activities. The premise of 501(c)(3) organizations is they must serve a public purpose and social activities must be "insubstantial". However, there are two sets of rules that apply to lobbying by 501(c)(3) organizations; based on whether they have chosen to file Form 5768 with the Internal Revenue Service (IRS).
Read more at: 501(c)(3) and Lobbying - The Basics on 4x4Voice
For additional information about Club and Association organization, see the 4x4Voice Club and Association Notebook