RUTHFULLY YOURS

John Rooney personified an era in which congressional Democrats eagerly aided and abetted the FBI’s running amok, as the bureau surveilled political activists who attracted Hoover’s ire. Rooney’s retirement in 1974 ushered in a radically different age, featuring rigorous and aggressive congressional oversight. A new generation of Democrats, led by principled progressives like Sen. Frank Church and Rep. Otis Pike, courageously proved ready and willing to expose and eliminate the abuse of Americans’ constitutional rights that had long been Hoover’s political bread and butter.

The Church Committee, along with decades’ worth of Freedom of Information Act releases, exposed once top-secret documents that FBI executives never imagined would see the light of day. These files detailed the scale of politically motivated misbehavior that had occurred when executive-branch controls and meaningful congressional oversight were absent. As a historian who cut his teeth on that copious record, I found it unimaginable that congressional Democrats, or American progressives generally, would ever return to championing unquestioned acceptance of FBI claims that its surveillance practices must remain hidden from the public.

But as Frank Church’s legacy faded, the FBI protested that the 21st-century bureau bore no relationship whatsoever to Hoover’s. In a 2016 speech, then-Director James Comey said that under the glass on his desk he kept a copy of a 1963 memo, signed by Attorney General Robert F. Kennedy, authorizing a wiretap on Martin Luther King Jr. “I keep it there in that spot,” Mr. Comey said, “to remind me of what we in the FBI are responsible for, and what we as humans are capable of, and why it is vital that power be overseen, be constrained, be checked.”