Trump endorsed U.S. Rep. Julia Letlow over Cassidy, in an unusual attempt to dislodge an incumbent senator. Cassidy voted to convict Trump in his second impeachment trial.

Sen. Bill Cassidy of Louisiana faces two challengers — one endorsed by the president — in Saturday’s primary, five years after voting to convict Trump.

Louisiana voters will participate in a revamped and stripped-down state primary Saturday and decide the political fate of an embattled Republican U.S. senator targeted for defeat…