The name of a C-3 organization may not be used in any political activity: the support of or opposition to a candidate for public office.
Prohibited political activity includes not only campaign contributions but also statements of support or opposition to a candidacy.
Statements of support for or opposition to a political party (as opposed to statements of support for a position on a specific issue) will be considered political activity. In other words, such support will be seen as support for or opposition to candidates.
Providing a forum for a candidate to speak is viewed as supporting the candidate. Providing a forum for opposing candidates (i.e. a candidates’ debate) to speak will still be viewed as supporting one candidate if the organization publicly supports that candidate’s policies.
A legislator or other elected official up for re-election is considered a candidate as of January 1 of the year in which the election is held.
Stationery of a C-3 organization or its organizational components (e.g. division, round table, committee) may not be used to make favorable – or unfavorable -- statements about candidates for public office.
Staff or leadership titles (e.g. president, councilor, executive director) in a C-3 organization may not be used by individuals in discussing their individual support for candidates, whether in writing or orally, in a public forum. A discussion list is a public forum.
Political activity is treated different from lobbying. Political activity is prohibited for C-3s. The IRS have stated they have "zero tolerance" for political activity by 501(c)3 organizations. Lobbying, which is the support of or opposition to legislation, is permitted within certain dollar limits. ALA does lobby -- and is well within specified limits.
The prohibition on organizational support for or opposition to candidates does not in any way prohibit staff, leadership, and members from expressing their personal views -- as long as organizational titles, stationery, forums, or other resources are not used.
The restrictions on political speech by C-3 organizations may be unfair; they may be illogical. But, they are the law, and the penalty for violation of these prohibitions is revocation of tax-exempt status, which would have a disastrous impact on the finances and goodwill of any non-profit organization.
To illustrate the level of scrutiny: A medical society had two of its members running for the state legislature. The society ran an article in its magazine, noting their candidacy and also noting how positive it would be for the society to have its members in the legislature. The organization lost its tax-exempt status.