The president is backing a primary challenge against the Louisiana senator, which may doom his political career.

Republican Sen. Bill Cassidy calls for full investigation after a Border Patrol agent shot and killed a man in Minneapolis during a DHS operation on Saturday.

Trump has long had a tenuous relationship with Cassidy.

Senator Bill Cassidy of Louisiana, a physician, reluctantly voted to confirm Robert F. Kennedy Jr. as health secretary. It didn’t appease President Trump.

Despite Trump's endorsement of Julia Letlow, incumbent Louisiana Senator Bill Cassidy remains confident he will be re-elected.

President Donald Trump encouraged Rep.

Louisiana state Rep. Julie Emerson (R) announced Thursday she was dropping her primary challenge against Sen. Bill Cassidy (R-La.) in light of Trump-backed Rep. Julia Letlow’s (R-La.) recent entrance into the race.

Cassidy’s call for a joint investigation comes amid deep tensions between state and federal officials in Minnesota. State officials have accused immigration agents of reckless tactics; Trump administration leaders have said state officials are refusing to cooperate and are inflaming anger at law enforcement.

Fresh off an endorsement from President Donald Trump, Rep. Julia Letlow of Louisiana is launching a U.S. Senate bid against fellow Republican and second-term Sen.

Rep. Julia Letlow announced Tuesday morning that she is running for Senate, after earning President Donald Trump's endorsement over the weekend for a Republican primary challenge against Sen.

Republican Senator Bill Cassidy has called for a full investigation after the killing of Alex Jeffrey Pretti by a U.S. Border Patrol agent in Minneapolis.