American campaign finance has its own vocabulary, much of it technical and easy to confuse. This glossary defines the terms that come up most often in coverage of super PACs and the broader political money system.
Terms are listed alphabetically. Where one definition relies on another, links connect them.
Jump to a Term
501(c)(4) · 501(c)(5) · 501(c)(6) · Bundler · Buckley v. Valeo · Campaign Committee · Citizens United v. FEC · Contribution Limits · Coordinated Communication · Coordination · Dark Money · Disclosure · Electioneering Communication · Express Advocacy · Federal Election Commission (FEC) · Hard Money · Hybrid PAC · Independent Expenditure · Independent Expenditure-Only Committee · Issue Advocacy · Leadership PAC · McCain-Feingold (BCRA) · Political Action Committee (PAC) · Redboxing · Single-Candidate Super PAC · Soft Money · SpeechNow.org v. FEC · Super PAC
501(c)(4)
A type of tax-exempt organization under section 501(c)(4) of the Internal Revenue Code, formally known as a “social welfare organization.” These groups are allowed to engage in political activity as long as politics is not their primary purpose. Unlike super PACs, 501(c)(4)s are not required to disclose their donors. This makes them the main vehicle for so-called dark money in American politics. Prominent examples include Americans for Prosperity (conservative) and the League of Conservation Voters (environmental).
501(c)(5)
A tax-exempt organization under section 501(c)(5) of the tax code, typically a labor union. Like 501(c)(4)s, these groups can engage in political activity within limits and are not required to disclose their donors.
501(c)(6)
A tax-exempt organization under section 501(c)(6) of the tax code, typically a business league or trade association — for example, the U.S. Chamber of Commerce. Like other “c-type” groups, 501(c)(6)s can spend on political activity without disclosing their donors.
Bundler
An individual who collects (“bundles”) campaign contributions from many other donors and delivers them to a candidate or committee. Bundlers are influential because they can deliver far more money than any individual donor could legally give on their own. Candidates often reward top bundlers with access, appointments, or recognition.
Buckley v. Valeo
A landmark 1976 U.S. Supreme Court decision that established the basic constitutional framework for campaign finance regulation. The Court held that the government can limit contributions to candidates (because of corruption concerns) but cannot limit independent expenditures (because doing so restricts protected speech). Much of modern campaign finance law, including the legal foundation for super PACs, traces back to this distinction.
Campaign Committee
The official committee of a federal candidate, established to raise and spend money on that candidate’s election. Campaign committees are subject to strict contribution limits and report their fundraising and spending to the FEC. A campaign committee is what most people mean when they talk about “the campaign.”
Citizens United v. FEC
The 2010 U.S. Supreme Court decision that held the government cannot restrict independent political spending by corporations and unions. The 5–4 ruling overturned earlier limits on corporate political speech and, together with SpeechNow.org v. FEC, cleared the path for the creation of super PACs. Citizens United is the most consequential campaign finance ruling of the modern era.
Contribution Limits
The maximum amounts that individuals and committees can legally give to federal candidates and party committees. The limits are set by federal law and adjusted for inflation. As of recent cycles, an individual can give a few thousand dollars per election to any one candidate. These limits apply to direct contributions; they do not apply to contributions to super PACs or 501(c)(4)s.
Coordinated Communication
A specific category of campaign communication that, under FEC rules, is treated as a contribution to a candidate rather than as an independent expenditure. If a super PAC’s advertisement is found to be coordinated with the candidate it supports, the spending counts as a (usually illegal) direct contribution. The FEC’s coordination rules are detailed but generally underenforced. See also coordination.
Coordination
The legal concept that distinguishes independent political spending from spending controlled by a campaign. Under FEC rules, spending is “coordinated” if it is done in cooperation, consultation, or concert with — or at the request or suggestion of — a candidate or party. Coordination is prohibited between super PACs and the candidates they support, but the line is widely seen as porous in practice. See also redboxing.
Dark Money
Political spending whose original sources are not publicly disclosed. Dark money typically flows through 501(c)(4), 501(c)(5), or 501(c)(6) organizations, which are not required to reveal their donors. When dark-money groups contribute to super PACs, the super PAC discloses the receipt — but the underlying donors behind the dark-money group remain hidden.
Disclosure
The legal requirement that political committees publicly report their fundraising and spending to the FEC. Super PACs, campaign committees, and traditional PACs are all subject to disclosure. 501(c)(4)s and similar groups are not.
Electioneering Communication
A category of political advertising defined by the McCain-Feingold law: broadcast, cable, or satellite ads that mention a federal candidate, run within 60 days of a general election or 30 days of a primary, and reach a relevant audience. Sponsors of electioneering communications must disclose them to the FEC, even if the ads do not explicitly call for the candidate’s election or defeat.
Express Advocacy
Political communication that explicitly urges voters to elect or defeat a specific candidate. The Supreme Court in Buckley v. Valeo limited federal regulation of communications that lack express advocacy, drawing what became known as the “magic words” line. Super PACs routinely engage in express advocacy through their independent expenditures.
Federal Election Commission (FEC)
The independent federal agency responsible for administering and enforcing federal campaign finance law. The FEC is structured as a six-member commission with no more than three members from any single party. For much of the post-2010 era, the agency has been deadlocked along partisan lines, limiting its capacity to issue rules or enforce existing ones. The FEC also operates the public database where super PAC and other committee filings are searchable.
Hard Money
Political contributions that are subject to federal contribution limits and disclosure requirements — that is, money raised under the strictest set of campaign finance rules. Candidate campaigns and party committees raise hard money. Super PACs do not.
Hybrid PAC
A political committee that operates two separate accounts: one for limited contributions to candidates (like a traditional PAC) and one for unlimited contributions used only for independent expenditures (like a super PAC). Hybrid PACs are sometimes called “Carey committees” after the court case that authorized them.
Independent Expenditure
A communication that expressly advocates the election or defeat of a clearly identified federal candidate and is made independently of any campaign or party. Independent expenditures are the legal category of spending that super PACs primarily make. They are not subject to limits but must be disclosed to the FEC.
Independent Expenditure-Only Committee
The formal legal name for what the public and press call a super PAC. The term reflects the defining feature: these committees can only make independent expenditures, not contributions to candidates.
Issue Advocacy
Political communication that addresses policy issues without expressly advocating for the election or defeat of a candidate. Pure issue advocacy is more lightly regulated than express advocacy, though electioneering communication rules apply to certain issue ads close to elections. The line between issue advocacy and express advocacy has been a persistent area of litigation and rulemaking.
Leadership PAC
A PAC established by a current or former federal officeholder, separate from that official’s own campaign committee. Leadership PACs are used to support other candidates, build political networks, and fund travel, events, and political operations. Members of Congress in leadership positions, or those pursuing them, almost always operate leadership PACs.
McCain-Feingold (BCRA)
The Bipartisan Campaign Reform Act of 2002, named for its lead sponsors Senators John McCain and Russ Feingold. The law banned soft money contributions to national party committees and tightened rules on electioneering communications. Several of its provisions were later struck down or weakened by court rulings, including Citizens United, but BCRA’s basic framework remains in force.
Political Action Committee (PAC)
A traditional, pre-2010 political committee that raises money to contribute to federal candidates. PACs are subject to contribution limits on both what they can receive and what they can give. They are typically associated with corporations, unions, trade associations, or ideological groups. PACs are distinct from super PACs, which can accept and spend unlimited money but cannot contribute to candidates.
Redboxing
An informal practice in which a campaign publishes — typically on a public webpage with red-bordered text — details about its strategy, advertising priorities, polling data, or messaging needs. Aligned super PACs can then consult these public materials and act on them without technically coordinating in violation of FEC rules. Redboxing is widely seen as a workaround for the coordination prohibition.
Single-Candidate Super PAC
A super PAC created specifically to support (or oppose) a single candidate, often a presidential or high-profile Senate contender. Single-candidate super PACs are typically founded by close associates or former staff of the candidate. Most major presidential candidates in recent cycles have had at least one allied single-candidate super PAC.
Soft Money
Political contributions raised outside federal contribution limits, historically given to political parties for “party-building” activities. Soft money to national parties was banned by McCain-Feingold in 2002. The term is sometimes used loosely today to refer to any money raised outside federal contribution limits — including super PAC and dark money funds — though this is not the original technical meaning.
SpeechNow.org v. FEC
A 2010 decision of the U.S. Court of Appeals for the D.C. Circuit that, applying the logic of Citizens United, held that contributions to groups making only independent expenditures could not be limited. Together with Citizens United, SpeechNow created the legal basis for super PACs.
Super PAC
A political committee, formally an independent expenditure-only committee, that can accept unlimited contributions and spend unlimited amounts to support or oppose federal candidates — but cannot give money directly to candidates or coordinate with them. Super PACs must disclose their donors to the FEC. They emerged in 2010 after Citizens United v. FEC and SpeechNow.org v. FEC.
This glossary is part of an ongoing, nonpartisan reference on super PACs and American campaign finance. For a fuller explanation of how super PACs work, see What Is a Super PAC?. For information on specific super PACs, see our directory.