“It’s an honor to share with you today that I’m officially announcing my candidacy for the United States Senate,” she told attendees at a breakfast in Baton Rouge on Tuesday, Politico and other outlets first reported.
Cassidy launched his re-election bid for a third term last year and has the backing of Senate GOP leadership.
Trump didn’t mention him by name when he backed Letlow, who has been toying with a run for months.
“Congresswoman Letlow called me this morning to say she was running,” Cassidy said in a statement.
“She said she respected me and that I had done a good job. I will continue to do a good job when I win re-election,” the Louisiana senator added.
“I am a conservative who wakes up every morning thinking about how to make Louisiana and the United States a better place to live.”