“How could you be so damn stupid? How could you do that?”

To Bill Clinton, during the Monica Lewinsky scandal in 1998, as reported in NewsMax.com https://books.google.com/books?id=8EkhAQAAMAAJ&q=%22You+stupid+f+%E2%80%94+ing+moron.+How+could+you+risk+your+presidency+for+this?%22 (9 December 2001)
Attributed

Source: White Oleander

June 27, 1992 Las Vegas, Nevada interview with Lederman.
From Subatomic World Explorer, as noted on American Academy of Achievement web site http://www.achievement.org/autodoc/page/led0pro-1 (URL accessed on October 20, 2008)

Source: Darkly Dreaming Dexter

Source: The Book Thief

329
1940s–present, Minority Report : H.L. Mencken's Notebooks (1956)
Context: My old suggestion that public offices be filled by drawing lots, as a jury box is filled, was probably more intelligent than I suspected. It has been criticized on the ground that selecting a man at random would probably produce some extremely bad State governors. [... ] But I incline to believe that it would be best to choose members of the Legislature quite at random. No matter how stupid they were, they could not be more stupid than the average legislator under the present system. Certainly, they'd be measurably more honest, taking one with another. Finally, there would be the great advantage that all of them had got their jobs unwillingly, and were eager, not to spin out their sessions endlessly, but to get home as soon as possible.

Source: Have a Little Faith: a True Story

"The Late Show"
("The Late Show" on YouTube) https://www.youtube.com/watch?v=UW5_Wr9sWeY
Late for the Sky (1974)