John McCain's risky choice of Governor Sarah Palin gives him a running mate who doubles down on his maverick image, may appeal to women, and counters Barack Obama's aura of new-generation change. But he may have undercut his best attack on the Democrat.
If Obama is an empty suit, as McCain has suggested, is Palin suited for the Oval Office herself?
She is younger and less experienced than the first-term Illinois senator, and brings an ethical shadow to the ticket. Just 20 months ago, she was mayor of Wasilla, Alaska, a town of 6,500 where the biggest issue is controlling growth and the biggest annual worry is whether there will be enough snow for the Iditarod dog-mushing race.
"On his 72nd birthday, is this really the one-heartbeat-away he wants to put in the White House?" said Representative Rahm Emanuel, the No 3 Democrat in the House of Representatives. "What does this say about his judgment."
But in addition to doubling down on his maverick image with the choice of Palin, McCain earned praise from evangelicals and other social conservatives who have been skeptical of him. Palin is a vocal opponent of abortion.
"Conservatives will be thrilled with this pick," said Greg Mueller, a conservative Republican strategist.
The price for that support could be high. Palin's lack of experience flies in the face of Republican charges that Obama is not ready to be commander in chief.
McCain himself has said he was determined to avoid a pick like Dan Quayle, the little-known Indiana senator George H.W. Bush put on his ticket in 1988 in a choice that proved embarrassing.
Quayle "had not been briefed and prepared for some of the questions", McCain said in April, while discussing his vice presidential search.
"I'm aware of enhanced importance of this issue because of my age," he said at the time.
Four months and one birthday later, McCain issued a statement announcing Palin that served to highlight the paucity of her experience.
"As the head of Alaska's National Guard and as the mother of a soldier herself," the statement said, "Governor Palin understands what it takes to lead our nation and she understands the importance of supporting our troops."
It is true, as the statement said, that Palin has a record of bipartisan reform. She has a growing reputation as a maverick for bucking her party's establishment and Alaska's powerful oil industry.
Palin campaigned on ethics reform in the 2006 Republican primary to defeat incumbent Gov Frank Murkowski, who served 22 years in the US Senate before winning the governor's seat in 2002.
She has an ethical issue. Alaska lawmakers on Monday approved an investigation into whether Palin abused her power in firing a public safety commissioner. Lawmakers say they want to know whether Palin was mad at the commissioner for not firing an Alaska state trooper who went through a messy divorce and ongoing child custody battles with Palin's sister.
She is 44. Obama is 47. She served in her statehouse 20 months. Obama served in his statehouse for eight years. Obama and Palin are running less on their resumes than on they are on their promise. The promise of change and new politics.
The difference is Obama wants the top job. Palin the No 2. But, as McCain suggested himself, his 72nd birthday is a reminder that age and experience matter.