When Americans think about campaign finance, they usually picture wealthy donors, political action committees and super PACs pouring money into elections.

But some of the most revealing money moves happen inside Congress itself.

Members of the U.S. House of Representatives routinely give campaign money to fellow members of their own party. These transfers make up only a small share of total campaign spending, but they can reveal something important: how parties reward influence, support vulnerable candidates and organize power from within.

In our recent study, my research colleague and I analyzed campaign contributions exchanged among House members from 2009 to 2022, using data from the Federal Election Commission. We looked at who gave money to whom across seven election cycles and asked a simple question: Are these decisions mostly ad hoc, or do they follow clear political patterns?

We found that they are far from random. Internal campaign giving reflects the structure of party politics in the House. Senior members and party leaders are more likely to be givers than receivers, and members facing pressure from outside spending are more likely to attract support from their party colleagues. We also found that Democrats and Republicans organize these campaign contributions differently.

Campaign contributions between House members are legal, common and publicly reportable. In practice, these transfers can help members build alliances, strengthen their party standing and direct resources to competitive races.

That makes these contributions politically meaningful even if they do not dominate the overall money race. More than a financial act, a contribution from one representative to another serves as a signal about who matters and who is vulnerable.

To study this, we treated member-to-member contributions as a network. Each House member was a node, and each contribution created a link from one member to another. This allowed us to track broad patterns over time rather than focusing only on high-profile lawmakers.

One of our clearest findings is that party insiders – meaning senior lawmakers and members in formal leadership roles – play a major role in steering campaign cash.

In our study, leadership included the speaker, party leaders, whips, caucus or conference chairs, and committee chairs or ranking members. Across the seven election cycles that we analyzed, about 79% of Democratic leaders and 71% of Republican leaders gave to at least one fellow House member, compared with 65% and 58% of nonleaders.

Leaders also tended to give to far more colleagues. In the 2021-22 election cycle, for example, Democrat Hakeem Jeffries gave to 76 fellow members in our network, Nancy Pelosi to 61, and Republican Steve Scalise to 192. Republican Jason Smith gave to 100 fellow members.

Public reporting shows the scale that these efforts can reach. During the 2021-22 cycle, Kevin McCarthy’s Majority Committee PAC reportedly contributed about US$4 million to select House Republicans in difficult reelection races.

Seniority mattered too, especially among Democrats. Longer-serving Democratic members were more likely to give and less likely to receive. This suggests that experienced members often help channel money toward colleagues with greater electoral need.

Our study also found a striking difference between the two major parties.

Democratic contribution networks were relatively stable over time. Their giving patterns remained more centralized, with money flowing repeatedly through a smaller set of members. That suggests a more consistent and hierarchical internal system for directing support.

Republican networks changed more over the same period. Early in our study, their money flows were also more centralized. But over time, contributions became less focused on a small core of recipients and were more likely to occur within smaller connected groups. That suggests support was being coordinated less through a single hub and more through clusters of politically connected members.

While Democrats do seem to rely more on a stable central structure, and Republicans appear to have moved toward a more dispersed system, it should not be taken to mean that one party is orderly and the other is chaotic. Both approaches offer their own advantages.

In today’s political language, a uniparty means the idea that Democrats and Republicans are basically one indistinguishable establishment. Our findings point the other way: At least in internal campaign finance, the parties are behaving in distinct ways.

We also examined the role of super PACs, which can spend unlimited sums independently to support or oppose candidates.

We found a consistent pattern across both parties: Members targeted by more super PAC activity were more likely to receive contributions from fellow party members and less likely to contribute to others themselves.

A concrete example shows why this matters. In the 2020 cycle, our data shows that outside spending reached about $8.4 million in Abigail Spanberger’s Virginia race for the House and about $7.36 million in Rep. David Valadao’s California race. When that much outside money floods a contest, it sends a public signal that the race is competitive and strategically important. Other lawmakers can see that signal and redirect their own money toward the colleague under pressure.

At a time when the role of money in politics remains deeply contested, such patterns remind Americans that campaign finance is not just a story about donors and interest groups. It is also about how politicians finance one another from the inside.

Those internal flows help show how parties build influence, protect vulnerable members and respond to election pressures. They also offer a window into broader differences between Democrats and Republicans.

More interestingly, it tells a story about party insiders making strategic choices about where money should go — and, in doing so, helping shape the balance of power in Congress.

This article is republished from The Conversation, a nonprofit, independent news organization bringing you facts and trustworthy analysis to help you make sense of our complex world. It was written by: Mayank Kejriwal, University of Southern California

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Mayank Kejriwal does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.