In picking little-known Sarah Palin as his running mate, Republican John McCain is betting, among other things, that having a woman on his ticket will make some voters take a different look at the race.

The possible upsides are clear-cut, and so are the potential risks.

The governor of Alaska is a new face on the national scene, and she might catch on with the voters. Her credentials as a social conservative will help reassure and perhaps energize a Republican base that has reservations about McCain.

Palin has a reputation as a reformer and someone not beholden to her party. The boldness of her selection bolsters McCain's maverick image.

And then there's the electoral calculation.

The obvious intent, confirmed by her own words yesterday, is to appeal to one of the larger groups of undecided voters in the race - women upset that Hillary Rodham Clinton is not on the Democratic ticket.

But it seems unlikely that women who backed Clinton would be drawn to the other party by a woman who is a strong opponent of abortion rights and any number of other Clinton positions.

Perhaps most important, the selection of someone with 20 months of experience leading a state with 670,000 residents undercuts one of the most effective arguments the McCain campaign has against the Democrats, that Barack Obama is not ready to be president.

The unavoidable question now is whether Palin is ready - and why McCain would want a running mate of whom that question could legitimately be asked.

McCain turned 72 yesterday and has a history of skin cancer. That seemed to make it essential that he choose someone of obvious presidential caliber. It's hard to argue that the 44-year-old former mayor of Wasilla, Alaska, and first-term governor meets that test, at least not in the traditional way.

Analysts were also already wondering how Palin, who made a point of mentioning yesterday that she is the commander of the Alaska National Guard as governor, will do in her debate in October against Democrat Joseph R. Biden Jr. and his 36 years in the Senate. She might benefit from low expectations.

"You know," said Rep. Heather Wilson (R., N.M.), "Gov. Palin has more executive experience than Sen. Obama, Sen. Biden and Sen. Schumer combined, because those guys have never run anything."

In introducing Palin in Dayton, Ohio, McCain heaped all manner of praise upon her. He called her a reformer with a fighting spirit, an executive with grit, integrity and good sense. He said she was in touch with the concerns of working people.

But he did not recite what has become the political boilerplate for such an occasion, that he had found someone who fulfills the only real criterion that matters: being qualified to serve should anything happen to the president.

On Thursday in Denver, with Barack Obama in mind, Minnesota Gov. Tim Pawlenty said:

"When you look at a candidate, you should ask two questions: What have you done, and what have you run? And when you look at those two questions, the answers are 'not much' and 'nothing.' "

In Palin's case, Democrats were saying yesterday, the answers might well be "not much" and "very little."

Speaking of her own career, Palin said yesterday: "It's always safer in politics to avoid risk."

It's a good thing for her that McCain decided not to choose the secure path.

Palin's naming also should end the idea that it matters where a running mate is from.

After eight years of a vice president from Wyoming, the nation is now looking at a successor from either Delaware or Alaska.

Each has three electoral votes, the minimum under the Constitution.