GOP Representative Thomas Massie’s chances of winning against challenger Ed Gallrein, who is backed by President Donald Trump, in the Republican primary for Kentucky’s 4th Congressional District have plunged one day before the election.
Massie had been the favorite on prediction markets. But early Monday, he had slipped to a 42 percent chance of victory on Polymarket, and 43.2 percent on Kalshi, down from 61 percent and 56 percent respectively as recently as Saturday, as in-person early voting ended.
Few Republicans in Congress have appeared to aggravate Trump as much as Massie, who has criticized the administration on a number of issues, including the Department of Justice’s handling of the Jeffrey Epstein files and the president’s foreign policy decisions.
Trump has regularly derided Massie on social media and endorsed Gallrein, a farmer and former Navy SEAL. The president’s endorsements often carry significant influence in Republican primaries, including just this past weekend when another Trump critic, GOP Senator Bill Cassidy, lost to a Trump-backed challenger in Louisiana.
Massie’s diminishing odds come after he faced allegations last week that he had tried to bribe an ex-girlfriend with undeclared income. He has denied the claims.
The high-profile contest in Kentucky has drawn significant spending with multiple billionaires investing in the race, which has become the most expensive U.S. House primary in history.
Newsweek has contacted Massie’s campaign outside regular working hours for comment via email.
Thomas Massie vs. Ed Gallrein: What Polls and Prediction Markets Show
As of reporting on Monday morning, Gallrein is the favorite on prediction markets, having outpaced his opponent.
On Kalshi, his chance of victory stands at 57.8 percent and on Polymarket, it stands at 58.7 percent, with Gallrein having surged into the favored position previously occupied by his opponent.
Prediction markets work by allowing traders to buy and sell contracts tied to current events and political outcomes. This, in turn, aggregates real-money wagers into probability estimates.
The polls have suggested a tight race. Now, recent surveys showing Gallrein in the lead.
A poll from Quantus Insights, which surveyed 908 likely voters on May 11 and May 12, found that 53 percent of voters planned to support Gallrein, and 45 percent planned to support Massie. 2 percent were undecided, and the poll has a margin of error of plus or minus 3.3 percentage points.
However, an earlier survey from Big Data Poll gave Massie a nearly 5-point lead, with 52.4 percent of respondents backing him and 47.6 percent saying they would support Gallrein. That survey polled 433 registered likely voters from April 3 to April 7 with a sampling error of plus or minus 4 percentage points.
The winner of the GOP primary will be the favorite against the Democratic candidate come the general election, as the district is solidly Republican, having backed Trump by more than 35 points in 2024.
Thomas Massie’s Feud With Donald Trump Explained
The president and the congressman have often clashed over the years, even though Massie endorsed Trump in the 2024 presidential election.
The two had already clashed during Trump’s first term, in March 2020, when Massie voted against a $2 trillion COVID-19 relief package, and Trump called for him to be thrown out of the GOP on social media.
Throughout the president’s second term, the relationship has soured.Massie has voted against Trump’s agenda on multiple occasions.
He has opposed the president’s foreign policy decisions, including the military strikes on Iran. Massie has also supported a War Powers Resolution, aimed at curbing Trump’s ability to declare war on Iran.
He has also broken with the president on economic policy, including on the One Big Beautiful Bill Act, passed by Congress last year, citing a lack of spending cuts.
Massie has also criticized the administration’s handling of the Epstein files. He led an effort alongside Democratic Representative Ro Khanna of California to force the release of files related to Epstein by the Justice Department.
Trump has regularly attacked Massie on social media. On March 11, he wrote, “I predict that ‘Representative’ Thomas Massie will go down as the WORST Republican Congressman in the long and fabled history of the United States,” and that he will “hopefully lose BIG,” in the primary.
The previous month, he had called him a “moron.”
“He’s an automatic ‘no,’ no matter what. If we did welfare reform, if we did the greatest thing in history for religion—no matter what we did, no matter how good it is, the greatest tax cuts, we just did the greatest tax cuts in history, he voted against. No matter what we do, this moron, no matter what it is…” said Trump.
Thomas Massie Hush Money Claims Explained
Lasty week, Cynthia West, a former congressional aide, alleged that Massie had tried to bribe her with undeclared income, allegations which he has denied and described as “unsubstantiated.”
West said Massie secured her a job in Congress in the office of Republican Representative Victoria Spartz of Indiana after the pair began a romantic relationship. West added that she ended the relationship after Massie began to engage in behavior she was not comfortable with.
West alleged that Massie offered her $5,000 after she said that she would file a wrongful termination complaint against Spartz. West said that Spartz had fostered a toxic working environment.
She added that she had declined this money, as well as a $60,000 settlement payment for “retaliatory discharge,” which would have required her to sign a nondisclosure agreement.
In a statement shared to Newsweek on Wednesday, Massie said: “It’s sad that a week before this election people are making false and unsubstantiated allegations about me in an obvious attempt to influence the outcome of this election.”
Spartz said in a statement shared to X that West was not fired. Rather, her office chose not to extend her temporary 90-day employment due to “concerning conduct by Ms. West.” She added that the complaint against her office came a few months later, and that she had denied this and refused to settle.
She defended Massie in her statement and wrote that she considers him to be “one of the strongest supporters of women in Congress and a defender of women’s rights among her GOP colleagues.”
How President Donald Trump Has Impacted Recent Primaries
Recent primaries have shown that Trump’s influence over the Republican Party remains strong.
On May 5, at least five of seven incumbent state senators in Indiana who had defied Trump and gone against his push for redistricting in the state, lost their races against challengers backed by the president.
On Saturday in Louisiana, Cassidy, a sitting U.S. Senator, finished third place in a Republican primary, bringing an end to his tenure in the Senate.
Cassidy had served in the Senate since 2015 but was unable to overcome the fallout that he had faced after voting to convict Trump during his second impeachment trial following the U.S. Capitol riot in 2021.
The president had made unseating Cassidy a priority, as he moved to purge those who have pushed back against him and those he perceived as detractors from the party.
So far, this has shown that Trump’s influence on GOP primary contests seems to have endured, despite polls showing a decline in his approval rating more generally. In early May, the president’s approval rating had slumped to its lowest point of this term at 35 percent in aggregate polling, while his disapproval rating sat at 64 percent, per CNN’s Poll of Polls.
