The FBI was corrupted from the get-go by J. Edgar. They concentrated on politically powerless bank robbers and gas station holdup crimes. Higher ups were protected for political support. “I’d rather having him in the tent pissing out, than outside the tent pissing in.” — Lyndon Johnson.
I disagree. They concentrated from the beginning on amassing a powerful portfolio of dirt on prominent politicians and citizens through a domestic spying and intimidation operation. Their paid informants were well placed, like the NKVD. Bank robbers were a justification, like the FBI movie and series. And Hoover’s famous tours.