DAYTON, Ohio — Republican presidential candidate Sen. John McCain introduced his running mate, Alaska Gov. Sarah Palin, at a raucous rally Friday, praising her "tenacity" and "skill" in tackling tough problems.
"She is exactly who this country needs to help us fight the same old Washington politics of me first and country second," McCain told supporters in Dayton.
Palin, who becomes the first woman to serve on a GOP presidential ticket and the first Alaskan to appear on a national ticket, echoed McCain's appeal to battle the status quo in Washington.
"This is a matter when principles ... matter more than the party line," she said to the cheering crowd of 15,000.
Palin made an immediate play for support from Democratic women, mentioning that she followed in the footsteps of Geraldine Ferraro, who was the Democratic vice presidential running mate in 1984.
Video: How Alaska's governor landed on national ticket She also referred favorably to Sen. Hillary Rodham Clinton, who drew 18 million votes in her unsuccessful run against Obama for the Democratic nomination.
"But it turns out the women of America aren't finished yet and we can shatter that glass ceiling once and for all," she said.
Palin's selection was a stunning surprise, as McCain passed over many other better-known prospects, some of whom had been the subject of intense speculation for weeks or months.
At 44, she is a generation younger than Sen. Joseph Biden of Delaware, who is Barack Obama's running mate on the Democratic ticket.
She is three years Obama's junior, as well, and McCain has made much in recent weeks of Obama's relative lack of experience in foreign policy and defense matters.
Unlike Biden, who attacked McCain sharply in his debut last week, Palin was indirect in her initial attempts to elevate McCain over Obama.
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"There is only one candidate who has truly fought for America and that man is John McCain," she said as the Arizona senator beamed. McCain was a prisoner of war for more than five years in Vietnam.
Election A to ZPalin has a strong anti-abortion record, and her selection was praised warmly by social conservatives whose support McCain needs to prevail in the campaign for the White House.
"It's an absolutely brilliant choice," said Mathew Staver, dean of Liberty University School of Law. "This will absolutely energize McCain's campaign and energize conservatives," he predicted.
Palin was elected Alaska's first woman governor in 2006, defeating Gov. Frank Murkowski in the GOP primary.
“I've been blessed with the right timing here,” Palin said before the election. “There's no doubt that Alaskans right now are dealing in an atmosphere of distrust of government and industry.”
She has proven to be a popular leader. Eighty percent of the state's voters gave her a "somewhat favorable" or "very favorable" rating in a July 2008 poll.
On Aug. 1, Palin scored a major victory when the Alaska Legislature passed a bill that authorizes her administration to award a license to TransCanada Alaska to build a 1,715-mile natural gas pipeline from Prudhoe Bay on Alaska’s North Slope to a hub in Canada.
The pipeline would be the largest construction project in the history of North America. If completed as hoped within 10 years, it would ship 4.5 billion cubic feet of natural gas per day. The United States imported about 10 billion cubic feet of natural gas per day in 2007.
Under investigation for firing
But Palin’s seemingly bright future was clouded in late July when the state Legislature voted to hire an independent investigator to find out whether she tried to have a state official fire her ex-brother-in-law from his job as a state trooper.
The allegation was made by former Department of Public Safety Commissioner Walt Monegan, whom Palin fired in mid-July.
Video: McCain picks Sarah Palin for VP “It is a governor’s prerogative, a right, to fill that Cabinet with members whom she or he believes will do best for the people whom we are serving,” Palin told CNBC’s Larry Kudlow in an interview on Aug. 1. “So I look forward to any kind of investigation or questions being asked because I’ve got nothing to hide.”
Palin also reacted to the indictment of Alaska Sen. Ted Stevens by calling it “very dismaying.” She added, “Hopefully though, this won’t be a distraction and get people’s minds off what has to be done in the grand scheme of things.”
As for the prospect of her being vice president, Palin told Kudlow that she could not answer the question of whether she wanted the job “until somebody answers for me what is it exactly that the VP does every day. I’m used to being very productive and working real hard in an administration. We want to make sure that that VP slot would be a fruitful type of position, especially for Alaskans and for the things that we’re trying to accomplish up here.”
'Hail Mary pass'
Democrats pounced on the news that McCain chose Palin, characterizing the move as a gamble.
"After the great success of the Democratic convention, the choice of Sarah Palin is surely a Hail Mary pass," New York Sen. Chuck Schumer said. "Certainly the choice of Palin puts to rest any argument about inexperience on the Democratic team."
But conservatives praised her anti-abortion credentials.
"Sarah Palin is a pleasant surprise for those of us who had hoped that Senator McCain would pick a principled and authentic conservative pro-life leader," former presidential candidate Mike Huckabee said.
Huckabee also used the Palin pick to reach out to women.
"Governor Palin ... will remind women that if they are not welcome on the Democrat's ticket, they have a place with Republicans," he said.
Palin is married to Todd Palin, a lifelong Alaskan who is a production operator on the North Slope and a four-time champion of the Iron Dog, which is described as “the world's longest snow-machine race.”
They have five children. Their son Track enlisted in the U.S. Army on Sept. 11, 2007. He is scheduled to be deployed to Iraq.
"He's a good American kid serving in the army for the right reasons," Palin said in a Friday interview with CNBC's Maria Bartiromo. "His Stryker brigade will be deployed Sept. 11. That's coming up here shorty."
Palin gave birth to their fifth child, Trig, last April. The baby boy has Down syndrome, a genetic abnormality that impedes a child's intellectual and physical development.
"When we first heard, it was kind of confusing," Palin said, according to an account in the Anchorage Daily News. She called the news "very, very challenging."
But she also related what she thought God would say to her family about her son: "Children are the most precious and promising ingredient in this mixed-up world you live in down there on Earth. Trig is no different, except he has one extra chromosome."
Palin made a name for herself in Alaska politics by serving as mayor of Wasilla for six years and going on to run unsuccessfully for the Republican nomination for lieutenant governor in 2002.
After her unsuccessful run, Palin received an appointment to the Alaska Oil and Gas Conservation Commission, where she ended up serving a role in an ethics probe into Republican Party Chairman Randy Reudrich, who was questioned about conflicts of interest with the oil industry.
The investigation ultimately forced Reudrich to resign from the commission.
Palin's role in the investigation left her a party outsider, but she was able to win the 2006 Republican gubernatorial primary against Murkowski, going on to win the general election by 7 points over her Democratic opponent.
During one debate before the primary, Palin said she was in favor of capital punishment in especially heinous cases such as the murder of a child. "My goodness, hang 'em up, yeah,” she said. Palin opposes abortion rights.
Born in Idaho, Palin moved to Alaska with her parents in 1964, when they went to teach school.
She received a degree in communications and journalism from the University of Idaho in 1987.
NBC News, msnbc.com and The Associated Press contributed to this report.