Mr. McCain, who died Saturday at 81, spent more than a half-century trying to teach us about torture — that it produces faulty intelligence, that “every man has a breaking point,” that military personnel derive a motivational pride from America having higher moral standards than its debased adversaries. “Your last resistance,” he writes in his latest book, “The Restless Wave” (written as usual with Mark Salter), “the one that sticks, the one that makes the victim superior to the torturer, is the belief that were the positions reversed you wouldn’t treat them as they have treated you.”

That lesson is fading from view in 2018, disregarded both by a president who believes that torture “absolutely works,” and by a #resistance cadre of ex-national security officials whose own brazen lies about the practice have yet to put a noticeable dent in either book sales or cable-TV contracts.

When Osama bin Laden “finally met the fate he deserved, the apologists for torture appeared in numbers on cable news shows and in the newspapers claiming bin Laden wouldn’t have been found without intelligence gained through the use of EITs” — enhanced interrogation techniques, Mr. McCain snarls in “The Restless Wave.” “In truth, most of the C.I.A.’s claims that abusive interrogations of detainees had produced vital leads to help locate Bin Laden were exaggerated, misleading, and in some cases, complete bullshit.”