This research brief describes the impact of all-candidate primaries on money in politics across special interests, campaign spending, and party meddling.
Many Americans are concerned about the impact of big money in politics. Specifically, they think campaigns are too costly, and elected officials are more responsive to their donors than their constituents.1 For example, recent survey research from the Pew Research Center found that over 70% of both Democrats and Republicans believe that there should be limits on the amount of money individuals and political organizations can spend.2 Further, over 80% of Democrats and Republicans believe big donors have too much influence over members of congress, while over 70% think special interests and lobbyists have too much influence as well.3
Unfortunately for those concerned about the role of money in politics, campaign finance reform is difficult to pass and implement, and the most impactful reforms would likely require a constitutional amendment. However, there is reason to believe the impact of money in politics can be reduced via a (perhaps) surprising source: all-candidate primaries.
This research brief describes the impact of all-candidate primaries on money in politics across three different domains, including:
Since 2012, ideological political action groups (PACs) have become the dominant outside spending groups in federal primaries. These groups — which tend to be funded by a small number of wealthy individuals and advance either right-wing or left-wing ideological priorities — now consistently spend more money in primaries than the historically-dominant PACs (representing business, labor, and parties) combined. The historically-dominant PACs tend to represent broader, less ideological interests that are tied to an industry. For example, the American Medical Association represents hundreds of thousands of healthcare professionals, while the National Air Traffic Controllers Association represents thousands of workers.
In 2022, the top spending PACs did not represent vast memberships or broad interests. They included Club for Growth Action on the right (funded by Richard Uihlein and Jeff Yass) and Protect our Future PAC on the left (funded by the disgraced former crypto billionaire Sam Bankman-Fried).4
The power of ideological PACs is at its peak in low turnout partisan primaries. In these contests, their money and mobilizing capability is far more impactful because they only need to persuade a relatively small number of voters in order to influence the outcome. Further, primary voters are more susceptible to special interests’ efforts to persuade them because a candidate’s party alone cannot determine their choice at the ballot box (as all candidates are from the same party). Voters are looking for differences among the candidates, and well-funded ideological interest groups can ensure that voters most frequently hear their messaging about the candidates.
Evidence suggests that all-candidate primaries limit the influence of special interest groups. There are numerous reasons we may expect this to be the case:
New research finds that all-candidate primaries significantly blunt the power of ideological PACs. Specifically, support from ideological PACs is only about one-third as impactful in all-candidate primaries as it is in partisan primaries.6 In partisan primaries, candidates who earn more support from ideological PACs gain a significant advantage: Receiving support from 20 ideological PACs corresponds to a 7.6 percentage-point increase in primary election vote share. In an all-candidate primary, however, receiving support from 20 ideological PACs only predicts 2.4-percentage point increase in vote share.7 In summary, this evidence suggests that all-candidate primaries can mitigate polarization by undercutting the influence of well-funded, unrepresentative, and ideological special interests.
Skeptics of primary reform sometimes argue that an all-candidate primary system will require candidates to raise and spend more money. Because all-candidate primaries tend to increase competition and encourage more candidates to run for office, some theorize that demand for campaign contributions will increase under the reform. If this theory were true, it would likely be the case that switching from partisan primaries to top-four all-candidate primaries, in particular, would lead to substantial increases in campaign fundraising. However, scholarly evidence from Alaska’s first elections held under Top Four suggests that this is not the case.
A comprehensive study of campaign finance in Alaska’s 2022 state legislative elections found no evidence that candidates raised more money under the new election system.8 In short, there were no dramatic changes in the financing of Alaska’s elections:
These findings are not particularly surprising considering that just one state legislative primary in Alaska featured more than four candidates. With that one exception, state legislative candidates knew they would advance to the general election, so they were not required to raise or spend much money during the primary season and could instead spend the vast majority of their funds during the general election. Ultimately, though only one cycle of evidence is available, reform in Alaska achieved the goal of shifting competition from the primary to the general election. This shift did not require candidates to raise more funds, but, rather, it merely shifted when they were required to campaign most vigorously.
Recent election cycles have seen party-aligned PACs — especially those aligned with the Democratic Party — spend money in the other party’s primary in hopes of propping up a candidate that it deems easier to defeat in the general election. Democratic groups engaged in this form of meddling extensively in 2022, spending over $50 million to prop up nine far-right candidates in federal and statewide contests.10 This kind of spending can hurt political parties, forcing them to run a candidate that they do not prefer, and that the opposing party actually had a hand in selecting. Further, partisan meddling of this type is intended to deceive voters; the PACs that run meddlesome ads portray themselves as trusted messengers, and, yet, they are anything but.
All-candidate primaries discourage this kind of meddlesome behavior because all candidates run on the same ballot. No party is guaranteed to have a candidate in the general election, which makes it much riskier for party-aligned PACs to spend money meant to boost the vote share of candidates from the other party. In partisan primaries, both major parties know they will have a candidate in the general election (provided they run a candidate at all), so the risk to the party of spending in the other party’s primary to boost a more extreme candidate is minimal.
Further, since primary turnout is often low, relatively small changes in the makeup of the electorate can have a significant impact. For example, if a party spends significantly to boost a candidate from the other party, the increased attention placed on this candidate could theoretically drive non-habitual primary voters to turn out. This could result in voters from the opposing party comprising a greater share of the electorate, and, potentially, lead to the meddling party being shut out of the general election (particularly in a top-two all-candidate primary).
In a top-four all-candidate primary, major parties may feel freer to meddle as it is virtually impossible for them to be shut out of the general election. However, the utility of spending money to boost an extreme member of the opposing party over a moderate member is lessened since both candidates stand a good chance of advancing to the general election regardless of the meddling (as there are four spots in the general election). Meddling only makes sense as a strategy when each party is both guaranteed to have a candidate in the general election and guaranteed to have exactly one candidate. When this is not the case, either the risks of meddling are too high or the utility is too low.
1 Cerda, Andy and Andrew Daniller, “7 facts about Americans’ views of money in politics,” Pew Research Center (October 2023).
2 “Money, power and the influence of ordinary people in American politics,” Pew Research Center (September 2023).
3 Ibid
4 Barton, Richard. “Nonpartisan Primaries & Special Interests: How reform mitigates the influence of ideological spending in elections,” Unite America (July 2024).
5 Ferrer, Joshua and Michael Thorning. “2022 Primary Turnout: Trends and Lessons for Boosting Participation,” Bipartisan Policy Center (March 2023).
6 Barton, Richard. “Nonpartisan Primaries & Special Interests: How reform mitigates the influence of ideological spending in elections,” Unite America (July 2024).
7 Ibid.
8 Albert, Zachary, Robert Boatright, Lane Cuthbert, Adam Eichen, Wouter van Erve, Ray La Raja, and Meredith Rolfe. “Election reform and campaign finance: Did Alaska's top 4 nonpartisan primaries and ranked-choice general elections affect political spending?,” Social Science Quarterly (July 2024).
9 Ibid.
10 Linskey, Annie. “Democrats spend tens of millions amplifying far-right candidates in nine states,” The Washington Post (September 2022).
