American campaign finance law requires the disclosure of most contributions to political campaigns and political action committees. Donors to super PACs are disclosed. Donors to party committees are disclosed. If you give money directly to a candidate, that gift is a matter of public record, searchable in FEC databases by anyone with a browser.
But there is a category of political spending that operates entirely outside this disclosure framework. Contributions to 501(c)(4) organizations — nonprofits organized under a provision of the tax code that permits a range of civic activities — are not disclosed to the public. When those organizations spend money on political advertising, the source of the funding remains invisible. This is what people mean when they talk about dark money.
The Legal Architecture
The 501(c)(4) designation was not designed for political spending. It was created for civic leagues and organizations promoting community welfare. The IRS rules allow these organizations to engage in political activity as long as it is not their "primary purpose" — a standard that, in practice, means they can spend up to 49 percent of their budget on what the IRS defines as political intervention without losing their tax-exempt status.
The Citizens United decision in 2010 did not create dark money, but it dramatically expanded the environment in which it operates. By holding that corporations and nonprofits have a First Amendment right to spend unlimited sums on independent political expenditures, Citizens United opened the door to large-scale political spending through entities that had previously been constrained by the assumption that such spending might be prohibited.
Who Uses It
Dark money flows through organizations affiliated with both parties, though the amounts and structures differ. Conservative dark money operations, including a network of organizations associated with the Koch political network and a parallel set of organizations connected to major Republican donors, have spent in the hundreds of millions per cycle. Liberal dark money organizations, including groups connected to major Democratic donors and the network built by organizations like the Sixteen Thirty Fund, have operated at comparable scale in recent cycles.
The bipartisan character of dark money spending is sometimes offered as an argument for why disclosure requirements would be neutral. Critics of that framing respond that the argument confuses the symmetry of the practice with the value of the information — voters on both sides would benefit from knowing who is funding the advertising they see, regardless of which party it favors.
"The argument that disclosure is somehow partisan because both parties use dark money is like arguing that financial fraud laws shouldn't apply because people of all backgrounds commit fraud."
The Disclosure Debate
Legislative proposals to require disclosure of large donations to 501(c)(4) organizations that spend on political advertising have been introduced in multiple Congresses. The DISCLOSE Act, first introduced in 2010, would require organizations spending more than $10,000 on federal elections to disclose donors who gave more than $10,000. It has passed the House twice and failed in the Senate each time, blocked by the filibuster.
The constitutional case for disclosure requirements is strong by historical standards. The Supreme Court has consistently upheld disclosure requirements as constitutionally permissible, most recently in Citizens United itself, which distinguished between independent expenditures (which could not be prohibited) and disclosure requirements (which could be required). The theoretical basis for a constitutional challenge to a broad disclosure law is limited — though the current Court's composition has introduced uncertainty into predictions based on precedent.
What the SEC Could Do
One path to disclosure that does not require congressional action runs through the Securities and Exchange Commission. A rulemaking petition filed by a coalition of law professors and good-government groups asked the SEC to require publicly traded companies to disclose political spending, including contributions to 501(c)(4) organizations. The SEC put the rulemaking on its agenda in 2013, then quietly removed it under political pressure. It has been on and off the regulatory agenda since.
If adopted, an SEC disclosure rule would cover only public companies — not private donors giving directly to nonprofits — but it would apply to a significant share of the corporate political spending that flows through dark money organizations.
The Information Value
The case for disclosure rests ultimately on a proposition about democratic accountability: that voters benefit from knowing who is funding the political messages they receive, and that politicians who are funded by undisclosed donors face fewer accountability pressures than those whose funders are public. That proposition is difficult to prove empirically — the counterfactual world in which all political spending is disclosed doesn't exist to study — but it has enjoyed broad support in American political tradition going back to the Founders' arguments about transparency in republican government.
What can be said with confidence is that the current system produces winners — donors who can spend on elections without accountability — and that those winners have strong incentives to maintain the arrangements from which they benefit. That dynamic, as much as any constitutional or policy argument, explains why the system looks the way it does.