From The Merchant of Venice Act 3, Scene II:
“In law, what plea so tainted and corrupt,
But, being seasoned with a gracious voice,
Obscures the show of evil? In religion,
What damned error, but some sober brow
Will bless it and approve it with a text,”
If I were to write a book on the political culture of the US under the Bush administration, this would probably be on the shortlist to be chosen as the epigraph.