It's not quite as ineffably koan-like as "The biggest self of self is self," but Gov. Mark Sanford delivered another parsing puzzler in his latest comments to the Associated Press, in which he admits to additional liaisons with his Argentinian mistress and further unspecified "line-crossing" with other women:
What I would say is that I've never had sex with another woman. Have I done stupid? I have.
Since we know that Gov. Sanford has been studying the Bible during his marital/political crisis, perhaps he was thinking of verses like these (from the New International Version):
For rulers hold no terror for those who do right, but for those who do wrong. Do you want to be free from fear of the one in authority? Then do what is right and he will commend you. (Romans 13:3)
Let him who does wrong continue to do wrong; let him who is vile continue to be vile; let him who does right continue to do right; and let him who is holy continue to be holy. (Revelation 22:11)
My people are fools; they do not know me. They are senseless children; they have no understanding. They are skilled in doing evil; they know not how to do good. (Jeremiah 4:22)
Then Jesus said to them, "I ask you, which is lawful on the Sabbath: to do good or to do evil, to save life or to destroy it?" (Luke 6:9)
In idiomatic English, you can do wrong/right/good/evil — or, in the negative, you can do no wrong/right/good/evil. But you can't just use any adjective in the do X frame to mean 'do that which is X.' What's special about wrong, right, good, and evil is that they can serve as adjectives or nouns ('that which is wrong,' 'that which is right,' etc.).
Stupid, on the other hand, does not generally mean 'that which is stupid.' Admittedly, it is possible to nominalize stupid, given the right context. For instance, there's the idiom stuck on stupid, famously used by General Russel L. Honoré in the aftermath of Hurricane Katrina (see YouTube clip here). And I could imagine someone saying my stupid on the model of my bad and other sporadic my Adj formations, but even that's a stretch.
(It's also possible to nominalize stupid to mean 'a stupid person.' The OED has this sense back to 1712, in a quote from Richard Steele: "Thou art no longer to drudge in raising the Mirth of Stupids..for thy Maintenance." Nowadays this mostly survives as a disparaging vocative, as in "It's the economy, stupid." And then there are those "I'm with stupid" T-shirts.)
So did Sanford have do wrong or do evil in mind, and then decide mid-sentence to use stupid instead? Perhaps he wanted to combine the sense of do wrong/evil with be/feel/look stupid. Certainly Sanford's behavior covers all of these unspoken possibilities.
(Hat tip, Barbara Zimmer.)