The Internal Revenue Service allows two types of organizations to claim tax exempt status designated as a 501(c)(4):
a. Social welfare organizations, and
b. Local associations of employees.
AARP is considered a social welfare organization under the Internal Revenue Code (IRC) 501(c)(4). The specific definition for a social welfare organization is “An organization [that] is operated exclusively for the promotion of social welfare if it is primarily engaged in promoting in some way the common good and general welfare of the community.”
The IRS’ website defines this further here and that page is summarized below. (Italicized language is added).
IRS: To be operated exclusively to promote social welfare, an organization must operate primarily to further the common good and general welfare of the people of the community (such as by bringing about civic betterment and social improvements).
This does not mean every person – or even every member – agrees with the organization on every issue; just that the primary function is to push for what the organization – here, AARP – believes is the common good and general welfare. Whether financial security, health care security, voting rights, housing issues or any of a number of issues AARP has been involved with since its inception, it is undeniable that AARP remains dedicated to the social betterment of people 50-plus.
IRS: Seeking legislation germane to the organization's programs is a permissible means of attaining social welfare purposes. Thus, a section 501(c)(4) social welfare organization may further its exempt purposes through lobbying as its primary activity without jeopardizing its exempt status...For more information, see Lobbying Issues (PDF).
This is a way of saying 501(c)(4) organizations can lobby Congress and state governments if that lobbying is aligned with their social mission. AARP has always and will continue to push for legislative fixes to social issues. This is the same today as it was when we fought against turning Social Security into risky private accounts or fought for adding a drug benefit to Medicare. During the Social Security fight, Republicans were questioning our motives; when we fought to add a drug benefit to Medicare, it was the Democrats. To AARP, if both sides are upset with us it just means that we’re doing our job and focusing on the needs of all people 50-plus, not just one political party or the other. Further, AARP discloses all its lobbying expenses in a quarterly form that’s publicly available here.
IRS: The promotion of social welfare does not include direct or indirect participation or intervention in political campaigns on behalf of or in opposition to any candidate for public office. However, a section 501(c)(4) social welfare organization may engage in some political activities, so long as that is not its primary activity. However, any expenditure it makes for political activities may be subject to tax under section 527(f).
AARP has never endorsed a candidate, given money to a candidate or supported one political party over the other. We do occasionally engage in bipartisan political activity; for instance, in 2008 we gave equal contributions to both the Democrat and Republican Party’s convention funds in order to help inject issues important to all Americans 50-plus into their discussions. Any political activity we do engage in – for instance, our activities at the conventions or when we host a debate between federal candidates – is reported, taxes are paid and that information is publicly available with our quarterly lobbying expenses here.