How big is the influence of money in US elections?

Record fundraising in the 2026 US midterms does not by itself decide election outcomes and often signals candidate viability, Vox reported.

The 2026 midterm cycle is projected to be the most expensive election cycle in US history, with candidates raising money at a record pace.

Big-donor groups tied to Israel policy, AI and crypto have become flashpoints in primary races in both parties. Michigan’s Democratic Senate primary, where Abdul El-Sayed won the nomination despite a major financial disadvantage and outside spending by groups including AIPAC, and Tom Steyer’s losing California governor bid after he spent more than $200 million of his own money.

Rising campaign cash has fueled voter concerns about corruption. A June Supreme Court ruling striking down limits on coordinated party spending with candidates further blurred the line between money raised directly by campaigns and money parties can spend on their behalf.

Danielle M. Thomsen, a University of California Irvine political science professor and author of the 2025 book “The Money Signal: How Fundraising Matters in American Politics,” told Vox that money matters most in low-information primaries. “Money isn’t irrelevant, but when you have other pieces of information, that can override money,” she said.

Thomsen said early fundraising is a prerequisite for candidates to be seen as viable, but not a guarantee of victory. “Almost all early money comes from individual contributors,” she said, adding that non-incumbent general election winners get about half their early money from max-out donors who give $6,600: “Most of our elections are driven by the upper class.”