Special counsel Robert Mueller’s final report is said to be close to completion and ready for submission to the Justice Department. There is even conjecture that it is already finished, but Mueller decided, or was perhaps persuaded by newly confirmed Attorney General William Barr, to delay submission until President Trump returns from the Southeast Asia talks with North Korean strongman Kim Jong Un. In a perfect world, the final report would be a nonevent. Alas, that is not our world, so Mueller’s conclusion will be only the beginning of a free-for-all, featuring Washington hypocrisy at its worst. The special counsel has conducted a legal probe, but the Trump-Russia narrative has always been political, more about ramifications for 2020 than accountability for 2016. In that imaginary, perfect world, the Mueller report would be a nonevent for three reasons. First and foremost, the report should not tell us much that we do not already know. Of course, there are fascinating facts to be learned. What was the precise nature of “collusion” between the Kremlin and the Trump campaign? What exactly happened at the Trump Tower meeting between top campaign officials and a lawyer connected to the Putin regime — the meeting at which Donald Trump Jr. expected to receive information that might devastate Hillary Clinton’s candidacy, but that we’ve been led to believe was a dud? Did the president obstruct the Russia investigation by firing FBI Director...