The artificial intelligence data center boom hit a roadblock on election night, further complicating the tech industry's historic expansion plans.

There were 41 local ballot measures in 10 states up for a vote on Tuesday that would place restrictions on the construction of data centers in different ways, according to Ballotpedia.

Voters sided against data centers in each measure except one in Harwood, North Dakota, according to an analysis by Ballotpedia and additional results gathered by CNBC on Wednesday. The lone exception was Harwood, North Dakota, where voters rejected an added review of industrial projects, including data centers.

Ohio alone accounted for more than half of the measures, with 21 on the ballot. The issue also played out at the top of the ticket, where Democrat Sherrod Brown ousted Republican Sen. Jon Husted after casting the incumbent as "the face of data centers."

The Buckeye State, which was named America's Top State for Business in 2026 by CNBC, has become a key battleground for the issue.

OpenAI announced in August that it secured 8 gigawatts of computing capacity at the PORTS-Pike Technology Campus in Ohio, the largest planned AI data center campus in the world. The first phase of construction is slated to begin this year, and capacity is expected to come online in phases starting in 2028, according to the project's website.

SoftBank and SB Energy are developing the Ohio data center campus in partnership with the U.S. Department of Energy. SoftBank is a major investor in OpenAI, and the two companies announced plans to invest $1 billion in SB Energy earlier this year.

Nvidia is backstopping the project, which could cost more than $500 billion in total.

Those plans could now run into resistance from the governor's mansion. Ohio's top office flipped blue on Tuesday, as Democrat Amy Acton, a physician, defeated Republican businessman Vivek Ramaswamy. Acton supports a "conditional moratorium" on data centers to ensure they cover 100% of utility costs and "exclusively build with union labor."

Heading into the election, the AI trade was already faltering on Wall Street, with chipmakers, neoclouds and other data center-related companies selling off in October on concerns about rising interest rates and overspending. The hyperscalers — Alphabet, Amazon, Microsoft and Meta — are each spending hundreds of billions of dollars a year on AI infrastructure to meet what they say is insatiable demand. All of those companies except Microsoft have turned cash flow negative in the process.

Getting data center projects off the ground may have just gotten a lot harder.

Communities in California, Florida, Illinois, Kansas, Maine, New Jersey, Nevada and Wisconsin also went to the polls to weigh in on the issue, according to Ballotpedia, and data centers were a key motivating factor for voters in matters up and down the ballot.

In a CNBC Voter Poll, 56% of voters said data centers were a crucial or major factor in their decision, with Democrats ranking the issue higher than Republicans.

Democrats who campaigned on pausing or regulating new projects won key races in Ohio, Wisconsin, Georgia and Texas, which is on track to become the world's largest data center market by 2030.

In one of the most significant results of the night for Democrats, Gina Hinojosa unseated Gov. Greg Abbott after blaming the Republican incumbent for the rapid buildout of data centers across Texas, saying he put the tech industry's interests ahead of local communities.

The losses came despite record spending from Silicon Valley to shape the 2026 midterms, with the GOP boasting a commanding advantage among the election's biggest donors. According to a CNBC analysis of Federal Election Commission records, 14 of the 20 largest donor groups backed Republicans almost exclusively. Crypto, AI and online gambling interests poured in more than $377 million.

Elon Musk, the cycle’s largest individual donor, spent at least $474 million, nearly half of it in Texas, and lost both of the state’s marquee races. It was a warning sign for the wave of tech companies and founders who left California for Texas in search of a friendlier business climate.

"Data centers in space looking pretty appealing right now," Musk wrote in a post on X.

Within hours of the polls closing, Democrats were already calling for AI executives to testify under oath.

Among the first to seize on the results was Rep. Greg Casar, the Texas Democrat who chairs the Congressional Progressive Caucus.

"The House Democratic majority must make it a top priority to protect Americans' jobs, freedom, and lives from AI billionaires," Casar said in a statement after Democrats were projected to win the House. "AI company CEOs should be called to testify under oath."

Casar also accused Republicans of being "bought and paid for by AI billionaires," arguing that voters had rejected that influence and warning Democrats to "hold them accountable instead of cashing their checks."

He said the data center fight is only the beginning.

"The revolt against data centers was one of the top issues of the 2026 election," he said. "And in a few years we will look back on it as just the early tremor of a much bigger AI earthquake upending American politics."

Rep. Robert Garcia, D-Calif., the presumptive next chair of the House Oversight Committee, summed it up in two words: "Lawyer up."

— CNBC's Ashley Capoot contributed to this article.

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