America has been inundated by the words dossier, memo, collusion, FISA, Carter Page. They all come back to the actions of one man: Christopher Steele. Which is why the only news that matters this week is that the former British spy’s credibility has been dismantled.

To the extent the U.S. press has focused on Mr. Steele, it has been to portray him in heroic epic style. A Washington Post profile told how Mr. Steele, a former MI6 agent who left in 2009 to start his own firm, felt “professional obligations” to take his dossier...