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 Aug. 29: NBC's John Larson has more on the woman nicknamed "Sarah Barracuda" in high school. Nightly News

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.

Surprising choice
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.

"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.

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Palin 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 Aug. 29: Praising her "fighting spirit" and "deep compassion," Sen. John McCain introduces Alaska Gov. Sarah Palin as his vice presidential running mate. MSNBC

“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.”

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