Fifteen Years Later, Citizens United Defined the 2024 Election

Citizens United v. Federal Election Commission, the Supreme Court’s controversial 2010 decision that swept away more than a century’s worth of campaign finance safeguards, turns 15 this month. The late Justice Ruth Bader Ginsburg called it the worst ruling of her time on the Court. Overwhelming majorities of Americans have consistently expressed disapproval of the ruling, with at least 22 states and hundreds of cities voting to support a constitutional amendment to overturn it. Citizens United reshaped political campaigns in profound ways, giving corporations and billionaire-funded super PACs a central role in U.S. elections and making untraceable dark money a major force in politics. And yet it may only be now, in the aftermath of the 2024 election, that we can begin to understand the full impact of the decision.

Citizens United, while purporting to address the specific issue of corporate speech, effectively invalidated almost all limits on so-called independent political spending (i.e., money that doesn’t go directly to a candidate or party, although it is often spent in close cooperation with them). The decision ushered in an era in which super PACs — outside groups that can fundraise and spend without limit as long as they maintain some notional separation from campaigns — now deploy massive amounts of money to influence American elections. Most of it comes from a minuscule group of the wealthiest donors and special interest groups, whose political influence has greatly expanded, as has the potential for political corruption.

The Court’s decision and others that followed shaped the 2024 election to a greater degree than any that came before it. Most notably, Donald Trump substantially trailed Kamala Harris in traditional campaign donations, which are subject to legal limits and must be disclosed. Yet he was able to compensate for this disadvantage by outsourcing much of his campaign to super PACs and other outside groups funded by a handful of wealthy donors. While such groups had spent hundreds of millions of dollars on ads in previous cycles, this was the first time they successfully took on many of the other core functions of a general election presidential campaign, such as door-to-door canvassing and get-out-the-vote efforts. Their activities unquestionably would have been illegal before Citizens United.

The donors who funded the president-elect’s campaign and leveraged other resources to help him — most strikingly Elon Musk, the world’s richest person and owner of the social media platform X (formerly Twitter) — have played an unprecedented role in his transition, including shaping policy and meeting with world leaders. Musk in particular was instrumental in derailing a bipartisan budget deal in Congress in December, weeks before the president-elect takes office. And he and other major donors are now poised to be pivotal players in Trump’s administration.

The Trump campaign is just part of the story, however. Candidates’ reliance on big money and donor secrecy that accelerated in the wake of Citizens United continued to grow. Outside spending on congressional campaigns, also mostly coming from a select few major donors, broke records. Funds from groups that do not have to disclose their donors at all, known as dark money, kept proliferating and became even harder to track. And candidates and parties continued to bend even traditional fundraising rules to raise more big money.

To be clear, the Supreme Court is not solely responsible for the legal changes that made these activities possible; a dysfunctional federal regulator — the evenly divided Federal Election Commission (FEC) — and Congress have also played important roles. But none of it would have been possible without Citizens United and related decisions, which have played an enduring role in putting the very wealthiest donors at the center of U.S. campaigns and governance.

In the Citizens United case, a conservative nonprofit group challenged campaign finance rules that ostensibly prohibited it from promoting a film that criticized then presidential candidate Hillary Clinton shortly before the 2008 Democratic primaries. The Supreme Court could have issued a narrow opinion ruling on that specific group’s activities, but instead a 5–4 majority took the opportunity to rule that virtually all limits on “independent” political spending from corporations and other outside groups violated the First Amendment.

This conclusion doubled down on the reasoning of a 1976 decision, Buckley v. Valeo. Buckley held that campaign expenditures, money spent to influence voters, were akin to political speech and could not be subject to legal limits (although campaign donations — money given to fund the expenditures of another, such as a candidate — could be limited). The only permissible justification for any limits would be the prevention of quid pro quo corruption (i.e., bribery).

After Buckley, the Court upheld some campaign safeguards, most notably in McConnell v. FEC (2003), in which it approved new restrictions on corporate and union campaign spending as well as the stricter contribution limits for political parties in the bipartisan McCain–Feingold campaign reform law, passed in 2002. Only a few years later, however, after a change in the Court’s ideological composition, Citizens United reversed these decisions in key respects. The Court’s ruling then set the stage for lower courts to hold that any group purporting to be independent of candidates cannot be subject to contribution limits.

The Court did not stop there. In 2014’s McCutcheon v. FEC, another 5–4 majority struck down overall contribution limits on individuals’ donations to candidates, parties, and PACs, known as aggregate limits. Because such groups often fundraise jointly, McCutcheon allowed them to directly raise contributions that far exceed the maximum that any individual can give to a single candidate per election (a little more than $3,000 in 2024).

Through each decision, the Court purported to preserve certain safeguards — most notably, transparency rules and independence requirements for outside groups like super PACs. But these protections are increasingly illusory because of weak rules and lax enforcement. The result has been torrents of political spending from a small group of the very wealthiest megadonors via super PACs, as well as steadily increasing amounts of untraceable dark money. Indeed, while Citizens United, like Buckley before it, claimed that independent spending carries no substantial threat of corruption so long as it is truly independent and disclosed, the 2024 election dispensed with that illusion forever.

As noted, the Supreme Court is not the sole cause for this changed landscape. Congress or the FEC could theoretically fill or at least mitigate many gaps in transparency rules and other laws. But the evenly divided FEC, which oversees campaign finance in federal elections, has usually done the opposite and instead created more loopholes. It almost never enforces laws prohibiting coordination that are supposed to keep candidates independent from allied super PACs and similar groups. Nor has it acted on numerous complaints related to untraceable money.

Congress, too, has repeatedly failed to implement safeguards. In the past 15 years, lawmakers have tried to pass meaningful reforms several times but have not succeeded. These efforts included bills that would ensure voters receive information about the large donors who spend money on campaign advertisements, improve FEC enforcement, shore up requirements to ensure that super PACs and other outside groups are truly independent of candidates and political parties, and create a viable public financing system for all federal elections.

In short, the other branches of government could do much more to update U.S. laws in light of the Court’s decisions. Those decisions themselves, however, were the catalyst for the most critical changes that shaped the 2024 race.

Here are some of the key ways Citizens United and other decisions shaped the 2024 campaign.

A handful of megadonors helped Trump narrow the fundraising gap with Harris, and one of them essentially helped run his campaign. The most striking consequence of Citizens United continues to be the expanded influence of the very wealthiest donors. Last year, donors who gave at least $5 million to super PACs in the presidential race spent more than twice as much as they did in 2020. Roughly 44 percent ($481 million) of all the money raised to support Trump came from just 10 individual donors. The top 10 donors supporting Harris accounted for nearly 8 percent ($126 million) of her campaign. For both candidates, most of this money came from outside groups like super PACs.

Of course, super PACs closely aligned with major candidates aren’t new. What made 2024 different was that campaigns were able to rely on these megadonor-backed, purportedly independent groups for core campaign activities. That was possible in part because of Citizens United and in part because the FEC — which already permitted significant cooperation between campaigns and super PACs — effectively eliminated most restrictions on the campaigns’ ability to outsource core voter outreach to these groups.

These changes set the stage for Musk in particular to play a central role in the election. He gave at least $277 million to two super PACs that supported Trump and other Republicans and effectively became part of the Trump campaign, frequently appearing center stage at rallies. One super PAC, to which he donated roughly $240 million, funded direct mailings, canvassing, and “spokesperson consultants” in swing states for Trump. The second, pointedly named RBG PAC after Justice Ginsburg, ran ads in swing states apparently intended to blunt criticisms regarding Trump’s record on abortion (and did not disclose who had funded its spending until after the election).

Musk was far from Trump’s only billionaire backer. Others included venture capitalist David Sacks, who hosted a fundraiser in Silicon Valley where the cheapest ticket was $50,000 ($300,000 bought a more intimate dinner with Trump); casino owner Miriam Adelson, who put more than $100 million into her own pro-Trump super PAC; packaging supplies magnate (and major donor to the election denial movement) Richard Uihlein, who sent $49 million in last year’s third quarter alone to his pro-Trump super PAC; and many other Big Tech billionaires. Collectively, these funders helped Trump make up much of his fundraising disparity with Harris.

Strikingly, while Trump relied heavily on super PACs, his actual campaign operated with a skeleton staff of only a few hundred people (compared with Harris’s more than 2,500 employees across battleground states alone) and little other infrastructure.

Of course, Harris had her own billionaire backers, most of whom also donated through super PACs and dark money groups, including tech moguls Dustin Moskovitz, Reed Hastings, and Ben Horowitz and Microsoft founder Bill Gates. In general, they do not appear to have taken on the same sort of central operational role in her campaign, however.

Megadonors also spent heavily in other federal races. Overwhelmingly, they had no ties to the states where their money landed, significantly exacerbating a trend in which more and more out-of-state money is flowing into congressional races. In marquee races in Arizona, Pennsylvania, and Ohio, for instance, national super PACs fueled by wealthy donors outspent several candidates’ campaigns and heavily influenced close primaries and general election races. Ohio’s Republican Senate primary attracted more than $20 million from nationally funded independent groups (with the two biggest donors hailing from Pennsylvania and Illinois), and Arizona’s Democratic primary for the Third Congressional District lured in $5.3 million from outside groups — twice as much as the campaigns themselves did.

Massive spending was not the only way that billionaires were able to shape the 2024 race. Most notably, Musk leveraged his ownership of the social media platform X to support his preferred candidates. X amplified Musk’s activity, including his pro-Trump posts, so that they appeared in the feed of every subscriber, and took other actions that likely benefited Trump and other candidates, such as hosting Ron DeSantis’s announcement of his own presidential campaign. Prior to Citizens United, the direct use of corporate resources to advocate for a candidate was typically limited to traditional press activities, which are exempt from most campaign finance rules. Now, however, a corporation like X — which, had it existed prior to Citizens United, would likely not have been categorized as engaging in press activity — has much broader leeway to harness its resources in support of its owner’s preferred candidates.

Dark money continued to dominate federal contests. While final numbers are not yet available, in 2024 anonymous sources directed more than $1 billion, at a minimum, to independent political committees supporting candidates on both sides of the aisle. The largest outside group supporting the Harris campaign was a super PAC funded by dark money groups. The Trump campaign also benefited from such secret spending, including by one group that reportedly raised $100 million over four years.

Dark money also played a pivotal role in many Senate and House races. The four dark money groups associated with House and Senate Democratic and Republican campaigns gave $182 million to their sister super PACs through the end of last September. These purportedly independent groups were, in practice, effectively part of each party’s campaign apparatus. This strategy is certainly not novel — for a decade, both parties have had shadow party super PACs through which they have been able to raise unlimited contributions. Still, while the numbers are not yet final, the flood of dark money likely broke records in 2024.

Thanks to legal loopholes and lax enforcement of current rules, tracking this surge of secret cash is becoming ever more difficult. Dark money groups are required to report spending for only certain activities, including independent expenditures and electioneering communications, which they increasingly do not run themselves. They are not required to disclose donations to other groups (although the recipients may have to disclose these donations) nor many types of campaign advertising, including most online ads, which surged last year. (The Brennan Center will release a comprehensive tabulation in the coming months.)

Candidates and parties turned to joint fundraising committees to foot their big bills in new ways. Joint fundraising committees are PACs formed by multiple candidates, parties, and PACs to raise money together. These groups took on a much more significant role for campaigns last year. Because McCutcheon invalidated aggregate contribution limits, joint fundraising committees can raise enormous amounts in direct donations. In theory, participants are supposed to allocate donations pursuant to a prearranged formula.

In 2024, however, an FEC deadlock created a new loophole, allowing these fundraising entities to themselves run campaign ads without allocating their costs, effectively allowing some participants to subsidize others. Both parties availed themselves of this loophole, but Republicans in particular exploited it. The National Republican Senatorial Committee spent millions of dollars through joint fundraising committees, mostly in battleground states like Wisconsin, Pennsylvania, and Nevada. Democrats, who originally urged the FEC to crack down on this practice, responded by saying they would use the same tactics for ads going forward. 

Fifteen years after Citizens United, federal campaign finance rules are more porous than at any time since Watergate. And with just a sliver of donors spending tens (even hundreds) of millions of dollars apiece, the opportunities for corruption are overwhelming. The Supreme Court has played a central role in eroding safeguards, but the other branches of government have done nothing to shore up rules in response.

While the chances for meaningful reform in the next Congress appear slim, state and local governments can and should lead the charge to make funding elections fairer and more inclusive. At the most basic level, states and large localities should require transparency for all political spending and specify that super PACs and other outside groups must be truly independent from candidates. They should eliminate loopholes that allow joint fundraising committees and similar entities to circumvent contribution limits. More states and localities should also join the many jurisdictions that already offer some form of public financing for elections, the most powerful solution to the problem of big money in politics. And state lawmakers can pass laws calling into question the legitimacy of Citizens United and the Court’s approach to campaign finance more broadly — as many antiabortion legislatures did with Roe v. Wade.

The expanded influence of wealthy donors and untraceable money draws opposition from the vast majority of Americans across virtually all political and ideological divides. With the Supreme Court unlikely to change course anytime soon, it will fall to other branches of government, including state and local policymakers, to enact commonsense reforms to help ensure that every American has a meaningful voice in the decisions that govern all of us.