Said by Jack Nicholson, but with an exclamation point:

"The truth? You can't handle the truth!"

in the 1992 Rob Reiner movie A Few Good Men. The scene was excerpted for use in the movie trailer, and it hints at some compelling secret that Nicholson's character, Colonel Jessup, is keeping from The American People.
In this way it is like the scene at the end of The Three Days of the Condor when the bad government agent explains in realpolitik terms the results of Robert Redford's do-good actions. It implies that Americans need to live within their web of fictions about themselves and their country.