That old bit of wisdom is an apocryphal quote from Martin Luther, but it was much on my mind watching the House Select Committee on Benghazi grill Hillary Clinton, as she cleverly outmanned Trey Gowdy and friends.

Sure, the committee extracted some interesting details during its 11 hours of interrogation. The most damning was that Sidney Blumenthal, the legendary fixer for the Clintons, had more direct access to the secretary of state during a crisis than America's ill-fated ambassador to Libya. He also passed on intelligence, surely none of it spoiled by his business interests.

But as a bit of political theater, it wasn't all that useful to Republicans. Diane Sawyer accidentally got more embarrassing quotes from Hillary Clinton in a 20-minute puff piece last year than Republicans got in hours of sustained examination from a congressional oversight panel.