Julia Letlow

Republican Senator Bill Cassidy has lost his bid for re-election in Louisiana's Republican Senate primary, in a result seen as a political victory for US President Donald Trump and his efforts to sideline critics within the party. With 99% of votes counted, Congresswoman Julia Letlow led the race with 44.8% of the vote, according to the Associated Press. State Treasurer John Fleming came second on 28.3%, while Cassidy secured 24.8%. Candidate Mark Spencer received 2.1%.

As no candidate won more than 50% of the vote, Letlow and Fleming will advance to a runoff election that is expected to determine Louisiana's next senator in the Republican-leaning state.

Trump, who endorsed Letlow in January, celebrated Cassidy's defeat on social media. "Bill Cassidy's political career is over," the president wrote, adding that "it's nice to see" the Louisiana senator defeated. He later criticised Cassidy for voting to convict him during his 2021 impeachment trial following the attack on the US Capitol on 6 January.

"His disloyalty to the man who got him elected is now a part of legend, and it's nice to see that his political career is OVER!" Trump posted.

In his concession speech, Cassidy did not mention Trump by name but appeared to criticise attempts to undermine democratic institutions. "Our country is not about one individual. It is about the welfare of all Americans and it is about our Constitution," he said. "And if someone doesn't understand that and attempts to control others through using the levers of power, they're about serving themselves. They're not about serving us. And that person is not qualified to be a leader."

Referring to disputed claims surrounding the 2020 presidential election, Cassidy added that in a democracy, even when results are disappointing, "you don't pout, you don't whine, you don't claim the election was stolen".

Letlow thanked Trump after the result, calling him "the best president this country has ever had". "Louisiana made it clear tonight: we are ready for strong conservative leadership that will stand with President Trump and never waver," she wrote on X.

Letlow entered politics after the death of her husband, Luke Letlow, who died from Covid-19 complications in 2020 before being sworn into Congress. She won the seat in a special election in 2021 and was re-elected in 2022 and 2024.

On the Democratic side, candidate Jamie Davis led the primary with 47.4% of the vote. Gary Crockett and Nicholas Albares were nearly tied for second place on 26.3%, separated by roughly 300 votes.