Bill Cassidy is the first elected U.S. senator to lose re-nomination since 2012. Former Republican Senator Richard Lugar was the last elected incumbent to lose his bid for re-nomination in 2012.

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…