What is a PAC?

One word covers two kinds of political money that behave nothing alike. Follow both, and campaign finance starts to make sense.

Picture two payments.

The first is a check for $5,000. It comes from a committee run by the National Beer Wholesalers Association, and it goes straight into a candidate's campaign account. It is capped by law. It is reported by name. And it is one of hundreds of nearly identical checks that committee has written, to Democrats and Republicans alike.

The second payment is not a check to anyone. It is a wall of television ads worth tens of millions of dollars, paid for by a group the candidate has never met and legally never can meet. Not one dollar of it touches a campaign account.

Both payments are called "PAC money." One word, covering both, is a big part of why campaign finance feels impossible to follow. So follow the two payments separately, and watch the confusion come apart.

The first payment

The classic PAC has existed since the 1940s. Here is the part most people get wrong about it: the money is not the organization's own money.

Start with the beer check. The committee that wrote it cannot legally reach into the association's own treasury—federal law bars corporations and incorporated groups from giving their funds to candidates, and that ban still stands. What they may do is sponsor a committee and let people connected to them chip in. In this case, that means people in the beer business. Their small personal donations get pooled, and the pool writes the checks.

The same is true of every company PAC you have heard of. When you read that Home Depot's PAC gave to a candidate, Home Depot did not write that check—its people did, through the same kind of pooled committee.

The rules around that pooling are strict. The FEC requires the giving to be voluntary. It limits who can even be asked—only the sponsor's own people, what the rules call its "restricted class." Asking the general public is prohibited. The filings record only where the money went.

And every check is capped. A PAC of this kind can give a candidate at most $5,000 per election. That figure comes from the FEC's current limits table, checked the day this was written.

Five thousand dollars does not buy an election. So why do organizations bother writing hundreds of these checks, year after year?

Look at who writes the most of them. The biggest direct PAC donor across all 535 current members of Congress, in our database, is the beer wholesalers, at $4.2 million across members' careers. After them come bankers, credit unions, car dealers, engineering firms, Home Depot, electric co-ops, Honeywell, home builders, and hospitals.

Not the list most people expect. But these industries share something: Congress writes the rules they live by. Alcohol distribution, banking, car sales, home construction—all shaped, in detail, by law. For businesses like that, being on good terms with whoever wins is not a luxury. The steady checks to both parties are what that looks like in the records.

One side note before the second payment. A politician can sponsor a PAC too, separate from their campaign. These "leadership PACs" mostly help fund colleagues' campaigns, and they are how a lot of influence gets built inside a party. When you hear that a senator "has a PAC," it is usually this.

The second payment

To understand the wall of ads, go back to 2010.

In January of that year, the Supreme Court decided Citizens United v. FEC. The ruling said corporations and unions may spend unlimited money on independent political speech—ads and messages made without any coordination with a candidate. It did not let them give to candidates. That old ban stayed.

That case is famous. What happened two months later is not. In SpeechNow.org v. FEC, a federal appeals court took the next step: if independent spending cannot corrupt a candidate, then a group that only spends independently should be able to raise unlimited money too.

That second, quieter ruling is what created the super PAC. The FEC's official name for it is "independent-expenditure-only political committee." The nickname exists because the real name does not fit in a headline.

So the super PAC is the classic PAC's mirror image. It can raise and spend without limit. And it gives candidates nothing, ever—its whole legal existence depends on staying independent.

The scale is a different universe. Remember the biggest traditional donor: $4.1 million, spread across decades. In our outside-spending data, one super PAC spent $509 million supporting candidates in recent cycles. Another spent $319 million attacking them.

The two worlds don't mix

Here is the part that surprised us. We compared our forty biggest check-writers against our forty biggest outside spenders. Not one organization appears on both lists.

That looked too clean, so we went hunting for a mistake in our own counting. We did not find one. The separation seems to be built into the system itself: the two kinds of money are reported in different filings, by different committees, under different rules. The trade groups writing capped checks and the war chests buying ads are simply different worlds. English gave them the same name, and that is where the confusion comes from.

Why it matters

If every political dollar is just "PAC money," then all of it sounds equally suspicious, and none of it can really be judged. The unusual hides behind the ordinary.

The two payments raise different questions. The $5,000 check asks: what does steady access buy? The wall of ads asks: who is actually funding this election? You cannot ask either question until you know which payment you are looking at.

That is why every profile on this site keeps them separate. Money given to a campaign and money spent about a candidate never share a total. To see both for your own representatives, type your zip code into the library.

All figures from the Money Behind the Ballot database, compiled from FEC filings; how we count is documented on the [methodology page]. Legal facts link to the Federal Election Commission's own pages, accessed August 2026.