Senator Bill Cassidy, targeted by President Trump, is walking a political tightrope as he battles other Republicans for the chance to seek a third term.
Senator Bill Cassidy was standing in line at a Home Depot in Baton Rouge, La., recently when a conversation with a woman in the store turned, as it often does in his home state, to his fraught relationship with the president.
“I say, ‘You know, I don’t really think President Trump likes me that much,’” Mr. Cassidy, a Louisiana Republican, recounted in an interview. “But we work really well together.”
That might be both an understatement and an overstatement.
Mr. Cassidy, who voted to convict Mr. Trump in his 2021 impeachment trial and who drew the ire of the “Make America Healthy Again” movement for his strong advocacy for vaccines, is now in the fight of his political life, largely because of the perception that he is insufficiently loyal to the president.
To many of his right-wing detractors, including the president, Mr. Cassidy committed the gravest possible sin when he was one of seven G.O.P. senators to vote to find Mr. Trump guilty of inciting an insurrection for the pro-Trump riot at the Capitol on Jan. 6.
That decision precipitated a major break between Mr. Cassidy, who spent six years in the House and has been a senator since 2015, and other Republicans in his state. It also triggered years of animosity and insults from Mr. Trump, who labeled Mr. Cassidy a “total flake” and endorsed a Republican congresswoman, Julia Letlow, to unseat him.
On Saturday, voters in Louisiana will take the first step in deciding whether to carry out Mr. Trump’s wish, casting their ballots in a Republican primary that has been entirely defined by which candidate most closely adheres to the president’s ideology.