The way it is done is to register as an Internal Revenue Code 501 (c) (3) organization which is exempt form income and properety taxes and the donations to which are also exempt, but cannot engage in influencing pending legislation or promote a candidate to a political office (but it can "educate public and legilsators" about various political issues), and then spin off a 501 (c) (4) "subsidiary" which can engage in the said political activities, but the donations to which are non-deductible.
Wojtek