I went through the court rulings, the FEC filings and the ad-tracking data to figure out how these groups actually work: where the money comes from, what the rules are (and how loosely they are enforced), why their ads are so nasty, and whether all that money buys anything at all.

01Two Pipes Into the Same Election

The simplest way to understand a super PAC is to compare it with a campaign. Money flows into American elections through two very different pipes.

That catch is the whole deal. A super PAC can raise and spend as much as it wants for or against a candidate, but it is not allowed to coordinate with that candidate's campaign. It also cannot hand money directly to candidates or parties. What it can do is run its own ads, send its own mail and knock on its own doors. Legally, it is an "independent expenditure-only committee," a name so clunky that a study of news coverage found it used a few hundred times, against more than 60,000 for "super PAC."

Super PACs do have to tell the FEC who gives them money. Anyone who gives more than $200 in a year gets named, and the group reports its ad spending within 24 to 48 hours as election day approaches. As you will see below, that disclosure has some large holes in it.

02How We Got Here

Here is the part that surprised me most: nobody ever set out to create super PACs. Congress did not pass a law inventing them, and the Supreme Court did not rule them into existence. They came out of an appeals court decision that the government decided not to appeal, plus two FEC opinions issued a few months later.

The key idea goes back to 1976. In Buckley v. Valeo, the Supreme Court said that giving money to a candidate can be limited, because a big check can buy influence, but spending your own money independently cannot, because the candidate is not part of the deal. Citizens United extended that to corporations and unions in January 2010. Two months later, the D.C. Circuit took the next logical step in SpeechNow.org v. FEC: if independent spending cannot corrupt anyone, then giving to a group that only does independent spending cannot either. The Justice Department declined to take that case to the Supreme Court, and the super PAC era began.

03From Millions to Billions

In their first cycle, 2010, super PACs spent well under $100 million. By 2012 total outside spending in federal elections passed $1 billion for the first time, and every presidential cycle and every midterm since has topped the one before it.

Source: FEC 24-month statistical summaries for each cycle. *The 2014 total covers congressional races only.

One detail jumped out at me. The number of super PACs has barely changed in a decade: there were about 2,700 in 2016 and about 2,500 in 2024. What exploded is how much money flows through each one. Most registered super PACs spend next to nothing. A handful of very large ones, many of them tied to party leaders in Congress or to presidential campaigns, do the heavy lifting.

04The One Rule, and How People Get Around It

The no-coordination rule is the only thing standing between a super PAC and a campaign, so it is worth knowing how thin it is in practice.

Redboxing. A campaign posts a page on its website, often with the key message inside a red box: "voters need to know" that the opponent did this or that. It adds some footage of the candidate looking senatorial. A super PAC then "finds" that public information and builds its ads around it. Because the material is public, it falls under a safe harbor in the coordination rules. One academic study found more than 200 federal candidates doing this in 2022 alone.

Candidates can raise money for super PACs. Under a 2011 FEC opinion, a candidate can ask donors to give up to $5,000 to a super PAC, and can headline that super PAC's fundraisers where much bigger checks are written. They just cannot personally ask for the unlimited part.

Door knocking can now be coordinated. In March 2024, the FEC ruled 4-2 that door-to-door canvassing scripts are not "public communications," so campaigns and outside groups can plan paid canvassing together. Outside groups poured money into exactly that in the 2024 presidential race.

The referee left the field. The FEC has six seats and needs four votes to do almost anything. It lost its quorum on April 30, 2025, when it fell below four commissioners, and by October 2025 only two commissioners remained. Without a quorum it cannot open investigations, issue rulings or enforce the rules it has.

05Why Their Ads Cost More

There is one thing super PACs traditionally cannot buy: a discount. By federal law, TV and radio stations must sell candidates airtime at their lowest unit rate in the 45 days before a primary and the 60 days before a general election. Super PACs get no such deal and pay whatever the market will bear.

The gap can be enormous. In early September 2026, according to an OpenSecrets analysis, Susan Collins's campaign paid $2,200 for a 30-second spot during Wheel of Fortune on Portland's WMTW. A super PAC supporting Collins paid $10,000 each for spots in a weekday rotation that same week, about four and a half times as much, and without a guaranteed air date. Super PAC money is plentiful, but every dollar of it buys less airtime than a candidate's dollar. (That gap may be narrowing: in September 2026 the Supreme Court reinstated, for now, an FCC notice extending the discount to joint fundraising committees, and some super PACs belong to those.)

06Why So Many Attack Ads

If you have ever wondered why outside ads are so relentlessly negative, the data backs you up. Here is the share of ads that were negative in the fall of the 2018 midterms, by who paid for them:

Source: Wesleyan Media Project, October 2018.

The reason is built into the law. Since 2002, a candidate's own TV ad has to include the candidate saying "I approve this message." If the ad is nasty, the backlash lands on the candidate. A super PAC ad carries only a line saying it was paid for by the group and "not authorized by any candidate or candidate's committee." If voters hate it, they hate a group with a forgettable name. So the division of labor is predictable: candidates run the warm biography spots, and the outside groups do the attacking.

This is not new. The infamous 1988 Willie Horton ad was paid for by an independent group, the National Security PAC, not by the Bush campaign. What changed after 2010 is the scale. Outside groups bought about 10 percent of the ads in federal races in 2000. In 2022 and 2024 they bought more than a third.

07Who Writes the Checks

Super PAC money is concentrated in a remarkably small number of hands. These are some of the largest disclosed totals a single donor or couple has given to super PACs and other political groups in one cycle:

Sources: AP (Musk), Axios (Adelsons), Fortune citing OpenSecrets (Mellon), CNBC as of November 2022 (Soros). Totals cover all the political groups each donor funded that cycle. In 2024 Miriam Adelson, Richard and Elizabeth Uihlein, Ken Griffin and Jeff and Janine Yass each also gave more than $100 million, according to a Washington Post tally.

And those are only the donors we can see. A super PAC has to disclose its donors, but if the donor is a 501(c)(4) "social welfare" nonprofit or a freshly formed LLC, the super PAC's report just lists the nonprofit or the LLC. The nonprofit does not have to say who funded it. The Brennan Center found that shell companies and 501(c) nonprofits gave super PACs about $1.3 billion in the 2024 cycle, more than the two previous cycles combined, and estimated total dark money in 2024 at a record $1.9 billion.

Timing is the other hole. A super PAC that files on a quarterly schedule can spend heavily right before a primary and not reveal its donors until the primary is over. In 2026, a group called Lead Left registered in late April, spent more than $3 million in May meddling in Democratic primaries, boosting some candidates and attacking others, and only in June, after the voting, did FEC filings show that all of its money had come from Conservative Americans PAC, a Republican-aligned super PAC.

08Inside the Books

Add up every super PAC's filings for the 2024 cycle and you get a picture of an industry, not a hobby:

Sources: FEC statistical summary of the 2023-24 cycle (April 2025); Brennan Center, May 2025.

Not every dollar becomes an ad. Media buyers have traditionally taken a commission of up to 15 percent of the ad budget, though big clients negotiate it down, and those fees are usually buried inside "media buy" lines on FEC reports. Consulting firms run by the people managing the super PAC can also do very well. A Sludge analysis found that the treasurer's firm at Future Forward, the main pro-Harris super PAC in 2024, received nearly $18 million for "media consulting." And when a super PAC winds down, it has no duty to refund anyone; Newt Gingrich's 2012 super PAC refunded $5 million to Miriam Adelson, and much of what was left went to consultants.

09Spending Against Their Own Side

Some of the most aggressive super PAC spending now happens in primaries, often against members of the party a group normally supports. Primaries are cheap, turnout is low, and in a safe seat the primary is the real election.

In 2024, the AIPAC-affiliated United Democracy Project spent more than $14.5 million to defeat Rep. Jamaal Bowman in New York's 16th District, which Sludge reported was more than any non-party outside group had ever spent on a House race, and $8.5 million against Rep. Cori Bush in Missouri. Both lost their primaries. The crypto industry's Fairshake spent more than $10 million attacking Rep. Katie Porter in California's Senate primary, and she finished third.

The 2026 primaries pushed it further. Kentucky's 4th District race, where Trump-backed Ed Gallrein beat Rep. Thomas Massie, drew about $37 million from the campaigns and allied super PACs combined, a record for a House primary, according to FEC filings tallied by Kentucky Public Radio.

10Does Any of It Work?

This is the question I most wanted answered, and the honest answer is: less than you would think, and less than the people raising the money would like you to believe.

The cautionary tales are spectacular. Jeb Bush's super PAC, Right to Rise, spent more than $80 million early in the 2016 primaries. By one count it aired 10,355 TV spots in Iowa, and Bush got about 5,200 votes there, roughly two ads for every vote. He finished sixth. In Texas in 2026, more than $100 million went into ads in the Republican Senate primary and runoff, overwhelmingly from Sen. John Cornyn and his allies, who outspent Ken Paxton's side by nearly 9 to 1. Paxton won anyway after Trump endorsed him.

The research lines up with the anecdotes. A 2018 analysis of 49 field experiments by political scientists Joshua Kalla and David Broockman found that the best estimate of the persuasive effect of campaign contact and ads in general elections is essentially zero. Ads seem to matter more further down the ballot, where voters know less about the candidates, and studies of Citizens United's effect on state legislatures found real but modest gains of a few points for Republicans. Super PACs also like to advertise impressive win rates, but many of those wins come from backing candidates who were already favored.

So the money is not a magic wand. In a high-profile race where voters already know the candidates, the last $50 million buys very little. Where it seems to matter most is in the races nobody is paying attention to, and in primaries, where a few million dollars can decide who is on the ballot in November.

• FEC: Buckley v. Valeo, Citizens United v. FEC, SpeechNow.org v. FEC case summaries; advisory opinions 2010-09, 2010-11, 2011-12 and 2024-01; contribution limits 2025-26; 24-month statistical summaries, 2011-12 through 2023-24.
• Center for Public Integrity, on the origin of the term "super PAC" (2014).
• Campaign Legal Center (2025) and Politico/FEC filings (2026), on redboxing and Lead Left. Congressional Research Service and Election Law Blog, on the FEC quorum.
• OpenSecrets via Maine Morning Star (September 2026), on TV ad rates in Maine; Election Law Journal study on redboxing (2024).
• Wesleyan Media Project (October 2018); Ridout, Fowler and Franz, The Forum (2025).
• Brennan Center for Justice, dark money in 2024 (May 2025); Sludge; AP; CNBC; Roll Call; CBS News.
• Sludge (2024), Kentucky Public Radio (2026) and AP, on primary spending; NPR/WFAE (2016) on Right to Rise; Kalla and Broockman, American Political Science Review (2018).