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Explainer

Citizens United Explained

The 2010 Supreme Court decision further tilted political influence toward wealthy donors and corporations.

Last Updated: January 29, 2025
Published: December 12, 2019
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The Supreme Court’s 2010 ruling in Citizens United v. Federal Election Commission is a controversial decision that reversed century-old campaign finance restrictions and enabled corporations and other outside groups to spend unlimited money on elections.

While wealthy donors, corporations, and special interest groups have long spent money on campaigns, their role has ballooned as a result of Citizens United and subsequent decisions, resulting in a fusion of private wealth and political power unseen since the late 19th century.   

What was Citizens United about?

Citizens United arose in 2007 when a conservative nonprofit organization challenged campaign finance rules that stopped it from promoting and airing a film criticizing then presidential candidate Hillary Clinton.

The Supreme Court eventually decided 5–4 that Citizens United was within its First Amendment rights to spend its money disseminating the film. But rather than opining solely on the case before it as it had been asked to do, the Court took the opportunity to entirely strike down century-old prohibitions on corporate “independent” spending — money that doesn’t go directly to a candidate or party.  This applied to labor unions as well. Lower courts applying the ruling extended it to invalidate almost all fundraising and spending restrictions for groups that purport to be separate from candidates, many of which are today known as “super PACs.”

What was the rationale for the ruling?

Justice Anthony Kennedy wrote for the narrow majority that limits on independent spending from corporations and other outside groups equate to limiting their speech and thus violate the First Amendment. This ruling doubled down on a 1976 decision, Buckley v. Valeo, which was the first case to say that campaign expenditures, or money spent to influence voters, was a type of “speech” and that the only permissible justification for most limits on money in politics was to prevent outright bribery, or as the Court’s opinion called it, “quid pro quo corruption.”

The justices who decided Citizens United held that independent spending could not pose a substantial risk of corruption on the erroneous assumption that the money wouldn’t be under the control of any single candidate or party.  They also assumed that existing transparency rules would require all the new spending they were permitting to be fully transparent, allowing voters to appropriately evaluate the messages targeting them.

Both assumptions have proven to be incorrect. While super PACs and other outside spenders are supposed to be separate from candidates and parties, they usually work in tandem with them — to the point where affiliated super PACs that can raise unlimited money are now integral to most major campaigns. Legal loopholes also mean that many of these groups can keep their sources of funding secret.

How has Citizens United changed elections in the United States?

The ruling has ushered in massive increases in political spending from outside groups, dramatically expanding the already outsized political influence of ultra-wealthy donors, corporations, and special interest groups.

In the immediate aftermath of Citizens United, analysts focused much of their attention on how the Supreme Court designated corporate spending on elections as free speech. But perhaps the most significant outcomes of Citizens United have been the creation of super PACs, which empower the wealthiest donors, and the expansion of dark money through shadowy nonprofits that don’t disclose their donors.

These trends reached new heights in the 2024 election. Billionaire-backed super PACs helped the winning presidential candidate close a substantial fundraising gap. These groups also went beyond just running supportive ads. A group funded by Elon Musk, the world’s richest person, took on core components of the winning campaign, including voter outreach operations. And dark money from groups that do not disclose their donors topped $1 billion, including at least $182 million that was funneled through groups closely aligned with the two major parties’ congressional leadership campaigns.

What are PACs and super PACs?

Political action committees, known as PACs, are organizations that raise and spend money for campaigns, or whose major purpose is to support or oppose political candidates or ballot initiatives. Traditional PACs are permitted to donate directly to a candidate’s official campaign, but they are also subject to contribution limits, both in terms of what they can receive from individuals and what they can give to candidates. For example, PACs are only permitted to contribute up to $5,000 per year to a candidate per election.

In the 2010 case Speechnow.org v. FEC, however, a federal appeals court ruled — applying logic from Citizens United — that outside groups could accept unlimited contributions from both individual donors and corporations as long as the groups don’t give directly to candidates. Labeled “super PACs,” these outside groups were still permitted to spend money on independently produced ads and on other communications that promote or attack specific candidates.

In other words, super PACs are not bound by spending limits on what they can collect or spend. Additionally, super PACs are required to disclose their donors, but those donors can include dark money groups, which make the original source of the donations unclear. And while super PACs are technically prohibited from working directly with candidates, weak rules that are supposed to enforce this separation have often proven ineffective.

Super PAC money, which largely comes from a small group of the very wealthiest donors, started influencing elections almost immediately after Citizens United. From 2010 to 2022, super PACs spent approximately $6.4 billion on federal elections. In the 2024 election, they set a record of at least $2.7 billion. Super PAC money has largely eclipsed donations by small donors (people giving $200 or less), despite funds from small donors growing.

For example, in the 2022 midterms, just 21 of the biggest donor families contributed $783 million and billionaires provided 15 percent of all federal election financing — most of which went to super PACs supporting congressional campaigns. These donors easily outspent the total given by the millions of small donors giving to House and Senate candidates that cycle.

What is dark money?

Dark money is election spending where the source is secret. Citizens United contributed to a major jump in this type of spending, which often comes from nonprofits that are not required to disclose their donors. Even before Citizens United, transparency in election spending had started to erode thanks to a disclosure loophole opened by the Supreme Court’s 2007 ruling in FEC v. Wisconsin Right to Life, along with inaction by the IRS and by the Federal Election Commission.

Citizens United allowed big political spenders to exploit the growing lack of transparency in political spending. This has contributed to a surge in secret spending from outside groups in federal elections. Dark money expenditures increased from less than $5 million in 2006 to more than $1 billion in the 2024 presidential elections alone.

Because dark money groups need only to report spending for certain activities, such as independent expenditures and electioneering communications, much of their spending has become increasingly difficult to track. Notably, these groups are not required to disclose donations to super PACs — which is where the majority of their spending now goes — or their spending for many types of campaign advertising, including most online ads.

Finally, because they can hide the identities of their donors, dark money groups also provide a way for foreign countries to hide their activity from American voters and law enforcement agencies. This increases the vulnerability of U.S. elections to international interference.

How can reformers address the consequences of Citizens United?

Over the long-term, Citizens United would have to be overturned by a constitutional amendment or the Supreme Court. In the meantime, there are policies that can combat the dominance of big money in politics and the lack of transparency.

At a minimum, it is critical to ensure that all large campaign donors are disclosed. Strong disclosure laws, like the one enacted in Washington, require groups spending significant sums on election activity to report their largest donors. Separately, lawmakers and regulators should pass stricter rules to prevent super PACs and other outside groups that can raise unlimited money from coordinating directly with candidates and parties. Existing laws also need to be fully enforced, which has been a longstanding challenge at the federal level thanks to dysfunction at the Federal Election Commission.

Further, candidates can be offered alternative means to fund their campaigns without relying on big donors and super PACs. The most effective way to do that is public campaign financing, specifically small donor matching, in which small private contributions are amplified using public funds. Fourteen states and dozens of large cities and counties have enacted some form of public financing, with other localities actively considering it. Such a system recently went into effect in New York State and candidates have widely adopted it, allowing them to raise far more in small donations from their own constituents.

Notably, overwhelming majorities of Americans across party lines have consistently expressed disapproval of Citizens United. At least 22 states and hundreds of cities have already voted to support a constitutional amendment to overturn it. And national polls routinely show that reducing the influence of money in politics is a top policy priority for Americans, a finding consistent across demographics including race, age, and political party affiliation.

Citizens United was a blow to democracy — but it doesn’t have to be the final word. Politicians can listen to what the vast majority of the public wants, even if big donors don’t like it.