Dark Money in Politics

What Is Dark Money

Dark money is political spending by groups that do not have to disclose their donors. The money reaches voters through television ads, digital campaigns, mailers, and contributions to super PACs, but the people who paid for it stay hidden. The Brennan Center describes the spenders as “nonprofits and shell companies that spend on elections without revealing their donors.”

Dark money is a legal category, not a verdict on the cause it funds. The test is simple: can a voter trace the money to the person or company that first gave it? If not, it is dark money.

How to Trace Who Paid for a Political Ad

Every federal political ad has to say who paid for it, and you can follow that name as far as the law allows. Sometimes the trail ends at a real donor. Sometimes it ends at a nonprofit, and that is where dark money begins.

The tools named above are the FEC’s campaign finance data, ProPublica’s Nonprofit Explorer, Meta’s Ad Library, Google’s Ads Transparency Center, and FollowTheMoney.org.

How the Law Created Dark Money

The system grew out of a Supreme Court ruling, a gap in tax law, and a 2016 spending rule. The timeline below shows the steps, and the paragraphs after it explain each one.

2010: The Supreme Court ruled in Citizens United v. FEC that corporations and unions could spend unlimited amounts on independent political ads. The Brennan Center notes the decision “was premised significantly on the Court’s assumption that all of this newly permitted election spending would be transparent.” Much of it was not, because nonprofits that fund ads do not have to name their donors. OpenSecrets counted $144 million in dark money contributions and reported spending in 2010 and $1.1 billion in 2024.

2013: The IRS told Freedom Path, a conservative nonprofit, that its activity was too political to qualify as a 501(c)(4). That dispute is still in court, as the next section explains.

2016: Congress added a rider to the 2016 spending law that bars the Treasury Department and the IRS from issuing or revising any guidance on how much political activity a 501(c)(4) may do.

2022: The Senate took up the DISCLOSE Act. The motion to end debate failed 49-49 on September 22, 2022: every Democrat and independent who voted said yes, and every Republican who voted said no (Senate roll call 346).

2024: Dark money set a record of more than $1.9 billion in federal races, by the Brennan Center’s count.

2025: A federal judge ruled the IRS’s 501(c)(4) test unconstitutionally vague.

The IRS Rule No One Can Define

The main vehicle for dark money is the 501(c)(4), a “social welfare” nonprofit that may spend on politics as long as politics is not its primary activity. The IRS has never said what “primary” means in numbers, and Congress has barred it from saying.

Freedom Path’s case shows what that gap looks like. The conservative nonprofit applied for 501(c)(4) status in March 2011. In September 2013, the IRS told it that its speech was too political and therefore inconsistent with the status, according to a case history by the law firm Wagenmaker & Oberly. Freedom Path sued in 2014, and again in 2020.

On September 30, 2025, a federal judge in Washington ruled that the IRS test is unconstitutionally vague, because the agency never fixed what counts as political activity or how much is too much. The judge considered sending the question back to the IRS but wrote that “that would not work here due to an obscure congressional appropriations rider.” The case is still open: the court asked both sides to propose a standard that is not vague, and a law professor filed a brief on that question in March 2026.

Enforcement had stalled long before the ruling. A 2019 ProPublica investigation found that thousands of complaints had come in since 2015 alleging that 501(c)(4) groups were breaking the rules, and that the IRS had not stripped a single group of its tax-exempt status for political spending in that period.

Both Parties Built Dark Money Pipelines

The usual route runs from hidden donors to a nonprofit, from the nonprofit to a super PAC, and from the super PAC to the ad a voter sees. The super PAC reports its donors, but the donor it reports is the nonprofit.

That one group accounted for “$1 out of every $6 from undisclosed sources in the 2024 election cycle,” the Brennan Center found.

The same pattern now funds the fight for Congress. From January 2025 through June 2026, the four main congressional super PACs, two for each party, raised $197.7 million from their own affiliated dark money groups, Issue One found. The two Republican-aligned super PACs took 58% of that money and the two Democratic-aligned super PACs took 42%.

Dark Money Hit a Record $1.9 Billion in 2024

By the Brennan Center’s count, dark money in federal races nearly doubled from 2020 to 2024. Its count includes money routed through super PACs, which is now the main channel.

The Brennan Center calls its $1.9 billion figure an undercount, because some kinds of undisclosed spending cannot be tracked. Direct ads by dark money groups were the main channel right after Citizens United, but since 2020 the groups have mostly moved money through large transfers to allied super PACs, the report found.

Some of the money bought ads meant to mislead. Building America’s Future, a 501(c)(4) that reportedly received funding from Elon Musk, gave more than $35 million to super PACs that ran seemingly pro-Harris ads “falsely suggesting that her campaign supported divisive policies,” the Brennan Center reported. Musk’s much larger spending, more than $290 million, ran mostly through America PAC, a super PAC that does name its donors.

The 2026 midterms had drawn about $1 billion in dark money by September. That figure comes from a New York Times analysis cited by the Brennan Center on September 22, 2026. Michael Waldman, the center’s president, wrote that the real total is higher and that the public may never learn where most of it came from.

Where the Disclosure Fights Stand

The fixes on the table would require names, not limit spending. None has become law at the federal level.

The DISCLOSE Act would require groups spending more than $10,000 on elections to name donors who give $10,000 or more. It would cover corporations, limited liability companies, unions, political organizations, and tax-exempt nonprofits other than charities. It would also require video and online ads they pay for to list their top five funders (bill text). Versions have been introduced repeatedly since 2010, and none has become law.

Most states require nothing of these groups. Only New York and Connecticut directly require 501(c)(4) groups to name their political donors. A few others, including Arizona, California, and Washington, have broader campaign disclosure laws that reach some of the money moving between groups.

The Honest Disagreement

Both sides of this debate invoke the First Amendment.

The case for donor privacy rests on history. In NAACP v. Alabama (1958), the Supreme Court protected the civil rights group from handing over its membership list to a hostile state. In Americans for Prosperity Foundation v. Bonta (2021), a 6-3 majority relied on that case to strike down California’s rule that charities give the state a list of their major donors. Groups across the spectrum argue that naming donors exposes them to harassment and chills speech. The astroturfing explainer covers that ruling in more detail.

The case for disclosure also comes from the Court. Eight justices in Citizens United upheld the disclosure rules in that case, reasoning that voters are entitled to know who is speaking. Disclosure advocates such as the Brennan Center argue that the ruling assumed that transparency, and that dark money groups now spend at a scale the Court did not foresee.

Where the sides meet is the threshold. The DISCLOSE Act would reach only donors who give $10,000 or more to groups spending more than $10,000 on elections, which leaves small donors to advocacy groups unnamed.

Not All Undisclosed Spending Is Dark Money

Dark money is a specific legal category. Not every political donation that lacks full transparency qualifies.

• Small individual donations are not dark money. Federal law does not require campaigns to name donors who give $200 or less, but that money goes directly to a regulated campaign.
• Lobbying is not dark money. Registered lobbyists file quarterly spending reports. See the lobbying explainer.
• Super PAC spending is not automatically dark money. Super PACs report their donors to the FEC. The spending becomes dark money only when a donor is a nonprofit or shell company that does not disclose its own funders.
• Issue ads are a gray area. A 501(c)(4) that runs ads about policy without naming candidates may fall outside the strict definition, even when its donors are hidden.

Frequently Asked Questions

Is dark money illegal?

No. The spending vehicles, 501(c)(4) nonprofits and super PACs, are legal, and nonprofits are not required to name their donors. The IRS can revoke a group’s tax exemption for too much political activity, but a 2025 ruling found its test too vague to apply, and Congress has barred it from writing a new one since 2016.

Do both parties use dark money?

Yes. In 2024, groups backing Democrats put up about $1.2 billion and groups backing Republicans about $664 million. The pro-Harris nonprofit Future Forward USA Action spent more than $304 million, and the pro-Trump nonprofit Securing American Greatness sent about $67 million to super PACs.

What is the DISCLOSE Act?

A bill (S.3991) requiring groups that spend more than $10,000 on elections to name donors who give $10,000 or more. Versions have been introduced repeatedly since 2010. The last Senate vote, in September 2022, failed 49-49 on party lines.

What is the difference between dark money and a super PAC?

Super PACs must disclose their donors. Dark money enters when the donor to a super PAC is a nonprofit or shell company that does not disclose its own funders. The super PAC reports the nonprofit’s name, and the person behind the nonprofit stays hidden.

How do I find out who paid for a political ad?

Start with the “paid for by” line, then search that name in the FEC’s campaign finance data. If the donor is a nonprofit, ProPublica’s Nonprofit Explorer shows its spending but not its donors. The dark money guide walks through each case, from TV and mail ads to Facebook and Google ads and state races.

What You Can Do

1. Trace the next political ad you see. Use the guide above: the “paid for by” line, the FEC’s data, and Nonprofit Explorer. Where the trail ends tells you whether the money is dark.

2. Support state disclosure reform. Campaign Legal Center, Common Cause, and Issue One work on disclosure laws in states. Only New York and Connecticut directly require 501(c)(4) groups to name political donors.

3. Ask candidates where they stand on the DISCLOSE Act. Ask whether they would cosponsor it, and whether they accept support from super PACs funded by dark money groups.

4. Tell your senators to cosponsor and pass the DISCLOSE Act (S.3991). Use the letter and call script below.