The 2026 midterm election cycle is projected to be the most expensive in US history, with candidates raising money at a record pace and donor groups tied to issues including Israel policy, artificial intelligence, and cryptocurrency emerging as flashpoints in primary races in both parties, according to an interview with Danielle M. Thomsen, a professor of political science at the University of California Irvine and author of the 2025 book 'The Money Signal: How Fundraising Matters in American Politics.'
2026 midterm cycle on pace to be most expensive in US history, researcher says money works primarily as viability signal
The 2026 midterm election cycle is projected to be the most expensive in US history, with candidates raising money at a record pace and donor groups tied to issues including Israel policy, artificial intelligence, and cryptocurrency emerging as flashpoints in primary races in both parties, according to an interview with Danielle M. Thomsen, a professor of political science at the University of California Irvine and author of the 2025 book 'The Money Signal: How Fundraising Matters in American Politics.'
The Democratic Senate primary in Michigan was described as the most expensive Democratic congressional primary in terms of outside spending, yet Abdul El-Sayed won the nomination despite a major financial disadvantage against outside interest groups including AIPAC. In California, billionaire Tom Steyer spent more than $200 million of his own money on a gubernatorial bid and lost.
In June, the Supreme Court struck down limits on how much political parties can spend in coordination with their own candidates, further blurring the distinction between money candidates raise directly and what parties can spend on their behalf, according to the article.
Thomsen's research focuses primarily on US House primaries. She argues that fundraising functions largely as a signal of viability to the public, party leaders, and media — a view she says practitioners broadly share but which had not been empirically documented before her work. A competing framework in political science holds that money matters for material goods such as buying advertising, office infrastructure, and staff.
Thomsen and graduate student Ryan Mundy collected data and wrote a paper examining why wealthy candidates are more likely to win. Their work found that rich candidates are more likely to raise early money, in particular large-dollar donations, which then yield greater returns in subsequent fundraising quarters. Among 407 non-incumbent general election winners from 2014 to 2024, 17 self-funded at least 90 percent of their first-quarter dollars and won; all were wealthy.
On small-dollar fundraising, Thomsen said research consistently shows small-dollar donors tend to be more liberal Democrats and more conservative Republicans, placing them at the ideological edges of their respective parties. She added that despite attention on small-dollar fundraising, most candidates still raise the bulk of their money from itemized donors — those contributing more than $200 — and most money continues to come from large donors.
- The source does not state what specific threshold of spending, if any, political scientists have identified as the point of diminishing returns for campaign expenditure.
- The source does not provide a response or position from AIPAC, Tom Steyer, Abdul El-Sayed, or any other campaign or outside group discussed.
- The source does not state the total dollar amounts raised or spent in the 2026 cycle to date that support the 'most expensive in US history' projection, nor does it identify who made that projection.
- The source does not state the peer-review or publication status of the Thomsen-Mundy paper on wealthy candidates.
- The source does not establish how the June Supreme Court ruling on party coordination spending is expected to affect the 2026 cycle in practice.
- The source does not specify the title or docket of the Supreme Court case that struck down limits on coordinated party spending.