When Did Lying To Congress Become Okay?

Lurking in this Steve Clemons post on the Bolton nomination is a key observation: "TWN is also alarmed at the seeming indifference that Senators Lugar and others have attached to the fact that John Bolton seems to have lied to the Committee on a broad number of questions -- and seems to have lied in a robust, emphatic manner." Right. When did lying to Congress become okay? It seems to have happened when George W. Bush decided to appoint all manner of Iran-Contra veterans to key posts notwithstanding the fact that some of them had previously been actually found guilty of lying to Congress while new evidence made it clear that others (John Negroponte in particular) had, in fact, been lying back in the 1980s. Now it's considered to be of little concern that Bolton pretty clearly lied.

Bracketing John Bolton and all partisan considerations, this is an odd and distressing development and I think it's genuinely weird that conservatives in general and Senate Republicans in particular are brushing it aside so casually. It's not as if Democrats are such paragons of virtue that the executive branch appointees of the next Democratic administration will be above engaging in such things when it suits them if it's been made clear that dissembling in congressional testimony is now going to be treated on the level of dissembling during a Meet The Press appearance. Our system of government relies, informally but crucially, on the proposition that people will be motivated not only by partisanship, but also by a sort of institutional jealously. Senators are supposed to stand on their privileges. Every member of the body loses a lot of authority when the "don't lie to the committee" norm collapses.

On a somewhat similar note, when did it start being the case that powerful committee chairs (i.e., Dick Lugar and, in his way, Chuck Grassley) feel compelled to defer to the White House rather than the reverse?