Has Donald Trump Already Lost the Senate?

President Donald Trump controls a 53-47 Republican Senate majority. But his campaign to defeat Republican senators who opposed him is backfiring, creating a rebellion among GOP lawmakers who are refusing to support his legislative priorities.

Four Republican senators have voted against the administration on key issues. The defections threaten Trump’s ability to pass his agenda in the final two years before the midterms.

Trump’s narrow three-seat Senate majority is leaving little room for error as divisions inside the Republican conference surface. Even a small number of defections can derail major legislation, forcing Republican leaders to scale back or abandon parts of the president’s agenda.

Senate Republicans Defy Trump on Iran War, Ballroom Funding

Senator Bill Cassidy of Louisiana lost his primary on Saturday to a Trump-backed opponent. Trump had endorsed Julia Letlow, calling Cassidy “a sleazebag, a terrible guy, who is bad for Louisiana.” The endorsement was part of Trump’s broader campaign to purge Republicans who opposed him on impeachment and other issues.

By Tuesday, newly freed from electoral pressure, Cassidy voted to force a Senate debate on Trump’s Iran war alongside Senators Susan Collins of Maine and Lisa Murkowski of Alaska. His vote tipped the measure to a 50-47 majority, a procedural win that would have been impossible just days earlier when Cassidy was still fighting for political survival.

Cassidy also announced his opposition to another White House priority, telling reporters Tuesday he would not support funding for a White House ballroom in the budget reconciliation bill. “I don’t expect to be voting for the ballroom funding,” Cassidy said, criticizing the administration’s decision to set up what he called a “slush fund” to reward political allies.

“People are concerned about making their own ends meet, not about putting a slush fund together without a legal precedent. We’re a nation of laws,” he said.

Collins, Murkowski, Cassidy, Tillis Form De Facto Opposition Bloc

After Cassidy lost his primary, he joined Senate Republicans willing to break with Trump on major votes. Collins, Murkowski and North Carolina’s Thom Tillis have all voted against some of the administration’s key priorities.

Collins and Murkowski backed war powers resolutions limiting the president’s authority in Iran. When Trump endorsed Ken Paxton over Senator John Cornyn in Texas, Collins pushed back sharply. “I don’t understand. He is an ethically challenged individual,” she said of Paxton. “John Cornyn is an outstanding senator and merited the president’s support.”

Tillis took a different path to independence. He announced last year he would not seek reelection. Once freed from the primary threat, he began openly blocking Trump nominees and opposing administration priorities.

The four senators represent a structural problem for the White House. With a 53-47 majority, Trump needs near-perfect unity to pass major legislation. Four reliable defectors make major legislation mathematically impossible to pass if senators adhere to party lines. Their numbers could grow if more senators lose primaries and face no further electoral consequences.

Which Democratic Senators Have Backed Trump Legislation Most Often?

Potentially clouding the math, however, is that some Democrats in the upper chamber have sided with Trump’s second-term initiatives. Senators John Fetterman of Pennsylvania, Jeanne Shaheen and Maggie Hassan, both of New Hampshire, and Angus King, a Maine independent who caucuses with Democrats, show the highest overall levels of Trump-voting alignment during his second stint in the Oval Office.

Regarding standalone legislation and policy bills—and discarding confirmations of administration officials—the most frequent aisle-crossing vote has belonged to Fetterman, with Nevada’s moderate Senators Catherine Cortez Masto and Jacky Rosen trailing closely behind.

Trump Endorses Ken Paxton Over John Cornyn

Senator Cornyn learned this week what it means to be deemed expendable by Trump. The president endorsed Paxton, the scandal-plagued state attorney general, over the two-term incumbent in a runoff scheduled for May 26.

“I’m really sad, I’m sad personally for John Cornyn and I hope he’s successful in his election regardless, and I’m sad for the institution,” one unnamed GOP senator told The Hill. “There’s no senator that works harder to make things happen around here, works harder to take care of his colleagues.”

Senate Majority Leader John Thune entered the weekly GOP lunch Tuesday afternoon, shortly after Trump announced his support for Paxton. Asked about Trump’s social media post, Thune measuredly replied: “It’s his decision.”

Analysts warn that a Paxton victory could weaken the Republican ticket in a general election against Democrat James Talarico. Some recent polls show Talarico leading both Paxton and Cornyn in general-election matchups. For Trump, the calculation is simple: Back a MAGA loyalist in the primary.

Trump’s Underwater Approval Ratings in Every Senate Battleground State

Trump’s approval rating is tanking in every critical Senate battleground state. Maine shows a negative 17-point approval. Michigan is at negative 14. Even Texas, a state Trump won by 14 points in 2024, shows him with a negative 3-point approval rating.

Matt Klink, president of Klink Campaigns, said this dynamic carries real political risk for Republicans.

“Six months out, public support is moving away from the party in power. If Republicans don’t change the story, the midterms could become a classic check-and-balance election,” Klink told Newsweek. “The danger for Republicans is that Trump’s approval becomes the emotional shortcut voters use to make decisions in races they otherwise haven’t fully engaged.”

Maria Cardona, political consultant based in Washington, D.C., said Republicans remain frozen by fear of crossing Trump, even as the political costs mount.

“It will be the question of the hour when the sun rises whether that has broken the chokehold,” Cardona told Newsweek. “But you never know the kind of cult-like behavior they engage in, and whether they still believe Donald Trump can do political damage to them.”

Trump’s 2026 Midterm Gamble

Trump is betting on the long game. His midterm strategy is straightforward: Back challengers like Paxton over incumbents like Cornyn, push MAGA-aligned candidates in competitive states and aim to emerge with a stronger Republican majority.

If Democrats pick up even a single seat Republicans were expected to hold, Trump’s majority shrinks further. But if his preferred candidates win in the midterms, he could emerge with a unified Senate majority. The current fractured coalition could be replaced by a bloc of Trump-aligned senators, consolidating control over his legislative agenda.