Promising to help Sen. John McCain rattle the Washington power structure, Palin mocked Sen. Barack Obama's resume and mantra of change in a highly anticipated speech to the Republican National Convention, ahead of the roll call that officially nominated McCain as the party standard-bearer.

"In politics, there are some candidates who use change to promote their careers, and then there are those, like John McCain, who use their careers to promote change," Palin, 44, declared in a defiant speech that drew repeated ovations.

She contrasted her service as mayor of her hometown - Wasilla, Alaska - to Obama's first public-service job in Chicago.

"I guess a small-town mayor is sort of like a 'community organizer,' except that you have actual responsibilities," she said.

After a torrent of news stories probing her background and questioning her qualifications for the national ticket, Palin took on what she portrayed as the elitism of the news media.

"I've learned quickly, these past few days, that if you're not a member in good standing of the Washington elite, then some in the media consider a candidate unqualified for that reason alone," Palin said. "But here's a little news flash for all those reporters and commentators: I'm not going to Washington to seek their good opinion - I'm going to Washington to serve the people of this country."

At that, the audience booed, and many turned to the press boxes, pointing and yelling: "Tell the truth1 Tell the truth!"

Palin devoted a portion of her speech to energy, a subject considered a strength of hers because her state is a leading producer of oil and natural gas. "We need American energy resources, brought to you by American ingenuity and produced by American workers," she said.

Last Friday, McCain named Palin as his running mate, tapping a once-obscure leader for history - she is only the second woman, and first Republican one, named to a major party's ticket, following Democrat Geraldine R. Ferraro in 1984 - and thrusting her into a glaring spotlight.

Since then has come word that Alaska lawmakers are investigating Palin for possible abuse of power in the dismissal of a state public safety commissioner. Documents released this week showed she had retained a private attorney to defend herself against the allegations. And, though she took credit for stopping the infamous $400 million "bridge to nowhere" project, a favorite rhetorical whipping boy of McCain's, it turned out Palin favored it when she was running for governor.

On Monday, Palin and her husband, Todd, announced that their daughter Bristol, 17, is five months pregnant, and that Bristol will marry the baby's father, Levi Johnston, 18.

Last night, at the end of Palin's speech, her family - plus Johnston - joined her on stage. Palin cradled her 4-month-old son, Trig, in her arms as cheers rose. McCain popped out to greet them all and could be seen whispering "very good job" to his running mate.

Earlier, McCain gave an interview to ABC News in which he defended his choice of his running mate, whom he called "a very dynamic person."

"This is what Americans want," he said. "They don't want somebody who has . . . necessarily gone to Harvard or an Ivy League school. She probably hasn't been to a Georgetown cocktail party. But you know what, she represents everything we want to see in government and America - change and reform and ethics and taking on the special interests."

He also cited one reason he considered Palin capable in foreign policy, saying: "Alaska is right next to Russia. She understands that. Look, Sen. Obama's never visited south of our border. I mean, please."

In a statement by Obama's campaign responding to Palin's speech, spokesman Bill Burton said last night that it was "well delivered, but it was written by George Bush's speechwriter and sounds exactly like the same divisive, partisan attacks we've heard from George Bush for the last eight years."

McCain offered Palin the vice presidential spot a week ago after one face-to-face meeting and one telephone call between them. That haste, and the various disclosures involving Palin since, have led some to criticize McCain's judgment in the important decision.

The McCain campaign pushed back hard yesterday against the media feeding frenzy, in a circle-the-wagons strategy that has worked to rally GOP activists for more than a generation.

Journalists are seeking to "destroy" Palin because she "isn't part of the old boys' network that has come to dominate the news establishment in this country," McCain senior strategist Steve Schmidt said.

Schmidt said the campaign would "have no further comment about our long and thorough" vice presidential vetting process. "This nonsense is over," he said, saying it was past time to move the conversation to war, energy and jobs.

Media-bashing became a theme of the evening yesterday, with speaker after speaker ripping reporters and commentators as snobs, drawing cheers.

Scathing ridicule of Obama was the other major theme. Three of the men who had challenged McCain for the nomination whipped the crowd into a frenzy with partisan attacks, in a full-throated return to politics after the preempting of convention business earlier this week because of Hurricane Gustav.

Former New York Mayor Rudy Giuliani, delivering a delayed keynote address, called Obama the "least experienced candidate for president of the United States in at least the last 100 years."

As the crowd leapt to its feet, Giuliani said: "Not a personal attack, a statement of fact - Barack Obama has never led anything. Nothing. Nada."

The crowd took up a chant: "Zero! Zero!"

Palin, he said, has led a city and a state, and cut taxes.

"They would have you believe that this election is about change versus more of the same, but that's really a false choice, because there's good change and bad change," Giuliani said. "Change is not a destination, just as hope is not a strategy."

Former Massachusetts Gov. Mitt Romney said electing Obama would return the government to the liberal philosophy that he said favors "dependency on government largesse" over initiative.

"The right course is the one championed by Ronald Reagan 30 years ago, and by John McCain today," Romney said. "It is to rein in government spending and lower taxes, for taking a weed-whacker to excessive regulation and mandates, for putting a stop to tort windfalls, and to stand up to the Tyrannosaurus appetite of government unions."

Romney accused Obama of dodging direct questions about the most important issue of the day during the recent Saddleback church forum, while "John McCain hit the nail on the head: radical Islam is evil, and he will defeat it! Republicans prefer straight talk to politically correct talk!"

Speakers also pressed the theme that Obama, unlike McCain, was unprepared for office in a dangerous world.

"Maybe the most dangerous threat of an Obama presidency is that he would continue to give madmen the benefit of the doubt," former Arkansas Gov. Mike Huckabee said. "If he's wrong just once, we will pay a heavy price."

Palin herself continued the attacks, at one point all but calling Obama a phony.

"In small towns, we don't quite know what to make of a candidate who lavishes praise on working people when they are listening, and then talks about how bitterly they cling to their religion and guns when those people aren't listening," she said. "We tend to prefer candidates who don't talk about us one way in Scranton and another way in San Francisco."