When Donald Trump claimed in March that he’d had his “wires tapped” prior to the election, the press and Obama officials dismissed the accusation as a fantasy. We were among the skeptics, but with former director James Comey’s politicized FBI the story is getting more complicated.

CNN reported Monday that the FBI obtained a warrant last year to eavesdrop on Paul Manafort, Mr. Trump’s campaign manager from May to August in 2016. The story claims the FBI first wiretapped Mr. Manafort in 2014 while investigating his work as a...