Federal Reserve chief Jerome Powell should be thanking Sen. Joni Ernst: The cost overruns her team dug up on mismanaged government projects make the Fed’s renovation overspending look almost modest.

Words like “ignorant,” “clueless,” “stupid,” “idiotic, “inane,” “moronic,” or “asinine” are harsh. They should not be used in reasoned argumentation, simply because they undermine the credibility of ...