(CBS/AP)  John McCain appeared Thursday night before a cheering crowd at the Republican Convention in St. Paul, Minnesota, and began the final stage of his presidential campaign, which many had once considered doomed to failure.

"Tonight, I have a privilege given few Americans -- the privilege of accepting our party's nomination for President of the United States," McCain said as the crowd broke into chants of "USA! USA!"

"And I accept it with gratitude, humility and confidence," McCain said.

Watch the video or read the full text of McCain's speech)

McCain, a POW turned political rebel, vowed Thursday night to vanquish the "constant partisan rancor" that grips Washington as he launched his fall campaign for the White House. "Change is coming," he promised the roaring Republican National Convention and a prime-time television audience.

"Fight with me. Fight with me. Fight with me. Fight for what's right for our country," he urged in a convention crescendo.

To repeated cheers from his delegates, McCain made only passing reference to an unpopular George W. Bush and criticized fellow Republicans as well as Democratic rival Barack Obama in reaching out to independents and swing voters who will pick the next president.

"We were elected to change Washington, and we let Washington change us," he said of the Republicans who controlled Congress for a dozen years before they were voted out of office in 2006.

As for Obama, he said, "I will keep taxes low and cut them where I can. My opponent will raise them. I will cut government spending. He will increase it."

"Appropriating Barack Obama’s own message may seem like a brazen political ploy, but for McCain, it’s less of a stretch than it would be for most other Republicans," said CBSNews.com senior political editor Vaughn Ververs. "As he and the rest of the speakers here in St. Paul emphasized over and over, McCain sees himself as a 'maverick' politician whose past political fights have been waged as much within his own party as without. And it’s that reputation - one which has enraged Republicans at times - which now become’s the GOP battle cry."

McCain's wife, Cindy, and ticketmate Sarah Palin and her husband joined him on stage as tens of thousands red, white and blue balloons cascaded from high above the convention floor.

Unlike Obama's speech a week ago, McCain offered no soaring oratory until his speech-ending summons to fight for the country's future.

But his own measured style left the hall in cheers, and as is his habit in campaign stops around the country, he stepped off the stage to plunge into the crowd after his speech. Palin joined him, embraced by the jubilant throng.

McCain touched only briefly on the Iraq war - a conflict that Obama has vowed to end. "I fought for the right strategy and more troops in Iraq, when it wasn't a popular thing to do," the Republican said, adding that in the months since, the long-suffering nation had been spared from defeat. McCain's appearance was the climax of the final night of the party convention, coming after delegates made Palin the first female vice presidential nominee in Republican history.

"She stands up for what's right and she doesn't let anyone tell her to sit down," McCain said of the woman who has faced intense scrutiny in the week since she was picked.

"And let me offer an advance warning to the old, big-spending, do-nothing, me-first, country-second Washington crowd: Change is coming," McCain declared.

McCain and Palin were departing their convention city immediately after the Arizona senator's acceptance speech, bound for Wisconsin and an early start on the final weeks of the White House campaign.

McCain, at 72 bidding to become the oldest first-term president, drew a roar from the convention crowd when he walked out onto the stage lighted by a single spotlight. He was introduced by a video that dwelt heavily on his time spent as a prisoner of war in Vietnam and as a member of Congress, hailed for a "faithful unyielding love for America, country first."

McCain faced a delicate assignment as he formally accepted his party's presidential nomination: presenting his credentials as a reformer willing to take on his own party and stressing his independence from an unpopular President Bush - all without breaking faith with his Republican base.

He set about it methodically.

"After we've won, we're going to reach out our hand to any willing patriot, make this government start working for you again," he said, and he pledged to invite Democrats and independents to serve in his administration.

He mentioned Mr. Bush only in passing, as the leader who led the country through the days after the terror attacks on Sept. 11, 2001.

And there was plenty for conservative Republicans to cheer - from his pledge to free the country from the grip of its dependence on foreign oil, to a vow to have schools answer to parents and students rather than "unions and entrenched bureaucrats."

A man who has clashed repeatedly with Republicans in Congress, he said proudly, "I've been called a maverick. Sometimes it's meant as a compliment and sometimes it's not. What it really means is I understand who I work for.

"I don't work for a party. I don't work for a special interest. I don't work for myself. I work for you."

Thousands of red, white and blue balloons nestled in netting above the convention floor, to be released on cue for the traditional celebratory convention finale.

Given McCain's political mission, it was left to other Republicans to deliver much of the criticism aimed at Obama.

In the race for the White House, "It's not about building a record, it's about having one," said former Pennsylvania Gov. Tom Ridge. "It's not about talking pretty, it's about talking straight."

McCain invoked the five years he spent in a North Vietnamese prison. "I fell in love with my country when I was a prisoner in someone else's," he said. "I was never the same again. I wasn't my own man anymore. I was my country's."

The last night of the McCain-Palin convention also marked the end of an intensive stretch of politics with the potential to reshape the race for the White House. Democrats held their own convention last week in Denver, nominating Delaware Sen. Joe Biden as running mate for Obama, whose own acceptance speech drew an estimated 84,000 partisans to an outdoor football stadium.

Before McCain accepted the nomination, his wife Cindy McCain took the stage to urge support for people caught up in Hurricane Gustav and introduced their seven children to the cheering delegates.

"He has shown the value of self-sacrifice by daily example and, above all John showers us with the unconditional love and support every family dreams of. I know what his children say of him," Cindy McCain said. "And his courageous service to America in war and peace leaves no doubt what our forefathers would make of him."

(Read the full text and watch the video of Cindy McCain's speech)

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