Knowing Obama's youthfullness would go against him McCain tried to neutralise it by picking Ms Palin (even younger than Obama) in order to pull some voters off Obama.
Also following Hillary's defeat to Obama, McCain hopes to gain 'some' women votes through Ms Palin as altenative to Hillary for voters who want women in top office.
So Ms Palin is there to win votes destined to 'young' Obama and 'a woman' Hillary (as she qualifies in both attributes - not only is she (Ms Palin) a woman but also she is younger).
Republican John McCain made a surprise choice of Alaska Gov. Sarah Palin as his running mate on Friday, (August 29 11:02) at DAYTON, Ohio - adding a political unknown to the presidential ticket who could help him appeal to women voters.
Palin, 44, a self-described "hockey mom," is a conservative first-term governor of Alaska with strong anti-abortion views, a record of reform and fiscal conservatism and an outsider's perspective on Washington.
"She's exactly who I need. She's exactly who this country needs to help me fight the same old Washington politics of me first and country second," McCain told a roaring crowd of 15,000 supporters in Dayton, Ohio.
Palin was chosen over more experienced and better known contenders as the Arizona senator grabbed the spotlight from Democratic rival Barack Obama one day after Obama accepted his party's presidential nomination before 75,000 flag-waving supporters at Denver's football stadium.
"The mission is clear. The next 67 days, I'm going to take our campaign to every part of our country and our message of reform to every voter of every background in every political party or no party at all," said Palin, joined on stage by her husband and family. She has five children ranging in age from 18 years to 5 months.
McCain and Palin will face Obama and his No. 2, Joe Biden, in the November 4 presidential election, with polls showing them running neck-and-neck.
The pick followed days of speculation about McCain's choice, with most of the better-known contenders like former Massachusetts Gov. Mitt Romney and Minnesota Gov. Tim Pawlenty eliminated over the last 24 hours.
'18 MILLION CRACKS'
Palin, former mayor of the town of Wasilla, is virtually unknown and untested nationally. That could hurt McCain's argument that Obama, 47, a first-term senator from Illinois, is too inexperienced to handle the White House.
Her selection was welcomed by social conservatives who sometimes have appeared reluctant backers of McCain. An opponent of abortion, Palin had her fifth child in April despite a pre-natal diagnosis of Down syndrome.
She could also help McCain appeal to disaffected supporters of Democrat Hillary Clinton, who lost a bruising primary to Obama. Palin noted the achievements of Clinton and Democrat Geraldine Ferraro, who in 1984 became the first woman vice presidential nominee of a major party.
"Hillary left 18 million cracks in the highest, hardest glass ceiling in America," she said, referring to the 18 million votes Clinton received in the primaries. "But it turns out the women of America aren't finished yet, and we can shatter that glass ceiling once and for all."
Palin would be the first woman U.S. vice president, adding another historic element to a presidential race that has been filled with firsts. Obama, 47, is the first black nominee of a major U.S. political party.
Palin made her mark as a reformer in a state hit by corruption scandals and could help McCain reinforce his own reform message, but the Alaska legislature has thrown a shadow over her reputation by launching an abuse of power probe.
Palin is accused of firing a highly regarded state public safety commissioner. The official charged he was released for resisting pressure from the governor's office to dismiss Palin's ex-brother-in-law, a state trooper who was involved in a contentious divorce and custody battle with her sister.
Elected in 2006, Palin is Alaska's first woman governor. She is also an avid sportswoman who would bring youth and vitality to the ticket. McCain turns 72 on Friday and would be the oldest person to take office for a first term in the White House if elected.
The two campaigns initially squabbled over who had more experience -- the young first-term senator from Illinois or the young first-term governor from Alaska.
"Today, John McCain put the former mayor of a town of 9,000 with zero foreign policy experience a heartbeat away from the presidency," said Obama campaign spokesman Bill Burton, adding that she would work to overturn abortion rights and continue Republican economic policies.
"It is pretty audacious for the Obama campaign to say that Governor Palin is not qualified to be vice president. She has a record of accomplishment that Senator Obama simply cannot match," McCain spokeswoman Jill Hazelbaker responded.
Obama, who called Palin to congratulate her, distanced himself from his campaign's statement, describing Palin's selection as "one more hit against the glass ceiling" and complimenting her as a compelling person.
"Obviously a terrific story, personal story. I'm sure that she will help make the case for the Republicans. Unfortunately, the case is more of the same. Ultimately, John McCain is at the top of the ticket," Obama said as he campaigned at a biodiesel plant in Monaca, Pennsylvania.
Palin and Democratic vice presidential pick Sen. Joe Biden of Delaware share at least one thing in common -- both have sons who are in the military and are being deployed to Iraq later this year.
The choice of a vice president rarely has a major impact on a presidential race. Palin will meet Biden, chairman of the Senate Foreign Relations Committee, in a debate in October.
McCain and Republicans open their national convention on Monday.
-source: UK news, yahoo website.