Nowadays, women can do a lot of things. We can hold high offices, wear trousers, ask men out, drink whiskey in public. What can't we do? Wink. Women winking is always, always inappropriate. Why?
Of course, this begs the question: is winking ever appropriate in anyone of either sex? Not really. Winking tends to be ridiculous by nature: patronizing, conspiratorial, bizarre, old-man roguish. In many cultures, winking is regarded as offensive or obscene; in ours, it's merely odd. But even then, it's generally a masculine purview — albeit an undesirable one.
Sarah Palin's infamous winks are a cautionary tale: the gesture managed to seem flirtatious, childish, dowdy and unprofessional all at once — to say nothing of culturally problematic. Her behavior made us think about winking and just why her co-option of the gesture was so shocking: it became clear that winking is probably one of the least serious gestures in the world. For one thing, winking deliberately disrupts the all-important eye contact that is crucial to communication; seems inherently untrustworthy; and, since not everyone can do it well, there's the ever present risk of tic-or-wink confusion. Winking, for all its conspiratorial overtones, is inherently divisive: it places the winker in a position of secret-sharer; the wink-ee, by contrast, has no say in whether or not he wants to be in on the joke. As such, it's somehow embarrassing for both parties.
If I had to hazard some armchair anthropology on why it's particularly problematic in women, I'd guess it has at least something to do with the fact that the gesture contorts the face in defiance of all notions of beauty, and there is something discomfiting about injecting deliberate distortion into everyday interaction. Then too, women are perhaps less free, given centuries of ingrained suspicion of our inherent moral fiber, to even suggest any notion of dishonesty, lack of openness, or complicity. To say nothing of the fact that as a naked come-on it's hardly going to win any points for traditional demureness.
That said, when done well — ie, not in a political debate — winking can be a valuable, just because so few people do it. One of my friends — a friendly, open person — regularly winks, not at men, but at other women. The gesture is odd, sure, but also strangely friendly and disarming. The same quality that renders man-on-woman winking knowing and creepy can, when used between peers, feel somehow intimate and conspiratorial — there is, after all, always some joke to share between like minds. Without wishing to overburden anyone with personal information, it should be said that I have been known, on occasion, to wink in instances of romantic intimacy — which is always unexpected. I also enjoy occasionally winking at too-cool-for-school types in aggressively hip situations. In a weird way, the very corniness of the gesture and the minor willingness to make oneself ridiculous is a means of seizing benign control of a situation.
Then, of course, you've got the Miraculous Winking Jesus, "who winks so that God would forgive us of our sins." And I really don't have anything to say about that.