Former special counsel Robert Mueller’s testimony Wednesday has been described as “excruciatingly awkward,” “confused,” “struggling” and “a stammering, stuttering mess.” I saw something completely different. From my perspective, after six hours of testimony, it was the 74-year-old career prosecutor and law enforcement officer who won the day. It wasn’t that close. Tasked with overseeing the most high-profile investigation of our time, Mueller managed to complete the investigation without appearing to have a partisan agenda, with both sides embracing him at times. Even Trump said he acted “honorably”—before he turned on Mueller as “conflicted” and partisan—and touted “total exoneration” soon after...