Letlow didn’t explicitly declare her candidacy in the wake of Trump’s endorsement, but signaled in a post on X that she was likely to get into the race.

“I’m honored to have President Trump’s endorsement and trust,” she wrote. “My mission is clear: to ensure the nation our children inherit is safer and stronger. This United States Senate seat belongs to the people of Louisiana, because we deserve conservative leadership that will not waver.”

Trump’s decision to endorse Letlow ends months of speculation among Republicans about if he would get into the race against Cassidy.

People close to Letlow last week were expecting a public endorsement from Trump in the coming days, according to two people.

But as the filing deadline drew closer, some fellow GOP lawmakers believed she would ultimately not get in. Cassidy has been telling fellow Republicans for months that senior White House officials had pledged to him that the president would stay neutral in his race — a promise first reported by POLITICO last year.

Yet even some fellow GOP senators were skeptical of that given Trump’s mercurial moods. Trump had also privately temperature checked some GOP lawmakers on their views about Letlow, according to one person with knowledge of the outreach.

Trump also called Majority Leader John Thune on Friday and told him that while he had not made a final decision, he was likely to endorse Letlow, according to two people with knowledge of the conversation. Thune encouraged Trump during the call to support Cassidy, the two people said, pointing to the president needing his vote this year and Cassidy’s role as HELP chair, which gives him a role in advancing Trump’s health care push.