To be tax-exempt under section 501(c)(3) of the Internal Revenue Code, an organization must be organized and operated exclusively for exempt purposes set forth in section 501(c)(3), and none of its earnings may inure to any private shareholder or individual. In addition, it may not be an action organization, i.e., it may not attempt to influence legislation as a substantial part of its activities and it may not participate in any campaign activity for or against political candidates.
"In addition, it may not be an action organization, i.e., it may not attempt to influence legislation as a substantial part of its activities and it may not participate in any campaign activity for or against political candidates.
"Substantial part" has never been defined by the IRS or anyone else, although general rule of thumb is no more than 10% of resources allocated to lobbying/legislation.
It does not mean & should not be interpreted as ZERO lobbying/legislative activities.