The Trump-Russia sleuthers have been back in the news, again giving Americans cause to doubt their claims of nonpartisanship. Last week it was Federal Bureau of Investigation agent Peter Strzok testifying to Congress that he harbored no bias against a president he still describes as “horrible” and “disgusting.” This week it was former FBI Director Jim Comey tweet-lecturing Americans on their duty to vote Democratic in November.

But the man who deserves a belated bit of scrutiny is former Central Intelligence Agency Director...