No sooner had the echoes stilled from Sen. Barack Obama's stirring acceptance speech in Denver than Sen. John McCain made a bold move. He picked as his running mate Gov. Sarah Palin of Alaska, who was not much known outside her home state and represents a maverick's gamble if ever there was one.

Mr. Obama was right in his speech: All across America something is stirring -- and now it has penetrated the conservative party. But the audacity of Mr. McCain's choice is a double-edged sword. At one stroke, he subverted the best argument Republicans had against the Democratic candidate: that Mr. Obama doesn't have the experience to be president. The Democrat addressed that by picking the Senate veteran Joe Biden.

Mr. McCain has done the reverse: He has gone with a candidate who makes Mr. Obama's resume seem substantial by comparison. Mrs. Palin is only 44 and has been governor for less than two years. Before that, she was mayor and a member of city council in Wasilla, a small Alaskan town. She has served with distinction, but she has not served long.

There's nothing in her paper-thin resume to suggest she knows much about foreign affairs, which Republicans have hitherto insisted was essential, and the issues that matter to America's great urban centers, given that Alaska is not typical of the rest of the country. While vice president is not president, the officeholder is only one heartbeat away. Mrs. Palin has a lot to prove about her fitness and readiness for high office.

Still, there's no denying her political appeal. A mother of five and staunchly pro-life, she will bring Christian conservatives into the McCain camp. With her life membership in the National Rifle Association and her fondness for fishing, hunting and snow-mobiling, plus her history as a high school basketball standout and a runner-up in the Miss Alaska beauty pageant, Mrs. Palin gives the McCain campaign a shot at picking up some of those disaffected Hillary Clinton voters in the socially conservative white working class. In her introductory speech, she explicitly said: "The women of America aren't finished yet ..."

But on the issues, there is much to dislike about Sarah Palin -- and other Clinton, not to mention Obama, supporters will be the first to point that out. But her candidacy is exciting -- and excitement can count for a lot in politics.