"Senator Bill Cassidy of Louisiana is a disloyal disaster," began a post by President Donald Trump on the day that the senator faced two challengers in his state primary.

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…