Holding the Senate Matters More Than Defeating Bill Cassidy

President Trump proved again Saturday that he can crush Republican dissenters by helping to defeat Sen. Bill Cassidy in a Louisiana primary. The question is to what end?

Mr. Cassidy earned Mr. Trump's eternal enmity when he was one of seven GOP Senators who voted to convict him after he was impeached a second time in 2021 after the Jan. 6 Capitol riot. It was a vote of conscience for Mr. Cassidy, but fealty counts for more than principle in the Trump universe.