Carl Levin, a liberal Michigan Democrat who served 36 years in the U.S. Senate, from 1979 to 2015, and who scared the wits out of America’s biggest CEOs by demanding explanations for shadowy schemes that hid billions in profits overseas and avoided vast corporate taxes at home, died July 29 in Detroit. He was 87.

Mr. Levin was regarded by Senate colleagues and Washington observers as a paragon of probity as the chairman of the Permanent Subcommittee on Investigations. He wielded subpoena power, huge briefing books, a big gavel, and an unquenchable zeal for grilling high-profile witnesses at public hearings.

According to The New York Times, he confronted the titans of JPMorgan Chase, Apple, American Express and other corporate giants, and extracted admissions about overseas banking havens and tax-avoidance maneuvers that rendered profits invisible and made tax burdens vanish into thin air.

“I will miss Carl Levin when he leaves the Senate after the next election — and you will too,” Joe Nocera, then an Op-Ed columnist for The Times wrote at the time. “Levin has done more than anyone to expose the scams, the conflicts, the wrongdoing and the sheer idiocy of the financial industry from the run-up to the financial crisis to the present day.”