The culture of celebrity giveth and the culture of celebrity taketh away. If you don't believe it, just look at Sarah Palin and Michael Jackson.

The collective preoccupation with celebrity may have originated in Jackson's entertainment milieu, but its dynamic of relentless scrutiny and remorseless — frequently cruel and satiric — comment now dominates much of our political journalism as well. If one takes the Alaska governor and her lawyers at their word that no devastating scandal looms, then she seems to have imploded under the weight of the political celebrity in which she initially reveled.

Who can blame her? Unless you've been schooled from adolescence — as Jackson had been — in the show-business ethic that any publicity is better than none and that taking oneself seriously is original sin, it can't be pleasant to hear yourself referred to as "Caribou Barbie" and to have your family made the butt of jokes. That, however, is the price of fame these days. Palin appears to have buckled under it, and her rambling holiday weekend news conference was one of those oddly disassociated discourses in which distressed Republican officeholders now seem to specialize.

Whatever she intended, it was difficult not to feel that one was watching Palin deliver her own political obituary. The culture of celebrity can be unforgiving of those who swim against its virtual tides.

Jackson, on the other hand, had all his unsavory controversies and off-putting personality traits washed away — not, as tradition would have it, in the "blood of the Lamb" but in the cloying sentimentality of the 24-hour news cycle, which has become one of the celebrity culture's great enablers.

A decade ago, University of Southern California cultural historian Leo Braudy realized that the culture of celebrity had entered a new phase — "certainly different in the quantity and the available media and the kind of penetration of imagery that washes over us every day and the inescapability of it," he said then. "It's possible now to keep watching the same story again and again 24 hours a day, and it gets that kind of drumbeat in the blood that there are certainly precedents for in the past but never so extensively."

Braudy's remarks in that PBS interview were prophetic, even though they could not fully anticipate the influence online journalism — with its preoccupation with "hits" and "traffic" — would come to exert over much of what remains of the serious news media.