Moreover, McCain was giving up his home turf of readiness to challenge Obama on his home turf of change. Can that possibly be pulled off? The calculation was to choose demographics over thematics. Palin's selection negates the theme of readiness. But she does bring important constituencies. She has the unique potential of energizing the base while at the same time appealing to independents.

This is unusual. Normally the wing-nut candidate alienates the center. Palin promises a twofer because of her potential appeal to the swing-state Reagan Democrats that Hillary Clinton carried in the primaries. Not for reasons of gender -- Clinton didn't carry those because she was a woman -- but because more culturally conservative working-class whites might find affinity with Palin's small-town, middle/frontier American narrative and values.

The gamble is enormous. In a stroke, McCain gratuitously forfeited his most powerful argument against Obama. And this was even before Palin's inevitable liabilities began to pile up -- inevitable because any previously unvetted neophyte has "issues." The kid. The state trooper investigation. And worst, the paucity of any Palin record or expressed conviction on the major issues of our time.

McCain has one hope. It is suggested by the strength of Palin's performance Wednesday night. In a year of compounding ironies, the McCain candidacy could be saved, and the Palin choice vindicated, by one thing: Palin does an Obama.

Obama showed that star power can trump the gravest of biographical liabilities. The sheer elegance, intelligence and power of his public presence have muted the uneasy feeling about his unreadiness. Palin does not reach Obama's mesmeric level. Her appeal is far more earthy, workmanlike and direct. Yet she managed to banish a week's worth of unfriendly media scrutiny and self-inflicted personal liabilities with a single triumphant speech.

Now, Obama had 19 months to make his magic obscure his thinness. Palin has nine weeks. Nevertheless, if she too can neutralize unreadiness with star power, then the demographic advantages she brings McCain -- appeal to the base and to Reagan Democrats -- coupled with her contribution to the reform theme, might just pay off. The question is: Can she do the magic -- unteleprompted extemporaneous magic, from now on -- for the next nine weeks?