The Steele dossier, that collection of incendiary allegations against Donald Trump compiled for the Hillary Clinton campaign by the former British spy Christopher Steele, was already widely discredited before the release of the Mueller report. Now, the report has hammered a few additional nails in the dossier's coffin. Mueller's work "underscored what had grown clearer for months," the New York Times reported recently, "that while many Trump aides had welcomed contacts with the Russians, some of the most sensational claims in the dossier appeared to be false, and others were impossible to prove." Mueller, the Times noted, included a number...