The first-term Alaska governor has already been good for McCain's fundraising efforts. Of the $47 million he raised in August, $10 million came in the three days after he announced he had chosen her to be his vice presidential running mate, the campaign said.
At the event in Democratic candidate Barack Obama's hometown, McCain also sought to reassure supporters who might be wary about Palin's experience level. She became governor in December 2006 and before that was mayor of small-town Wasilla, Alaska.
"She was thoroughly vetted and I'm proud of the experience and the talent she brings to our ticket, and she will bring to the presidency and vice presidency of the United States of America," McCain said.
McCain also repeated his line against Obama from earlier in the day, when he and Palin criticized the Illinois senator for the amount of money he has requested for his home state, even though Alaska under Palin's leadership has asked Washington for 10 times more money per citizen for pet projects.
At a rally in swing state Missouri, McCain and Palin accused Obama of requesting nearly $1 billion in earmarks for Illinois. The new line of attack came after Obama made his first direct criticism of Palin over the weekend, using the topic of earmarks, which are special projects that lawmakers try to get for their districts and constituents.
"Just the other day our opponent brought up earmarks - and frankly I was surprised that he would even raise the subject at all," Palin said. "I thought he wouldn't want to go there."
Obama hasn't asked for any earmarks this year. Last year, he asked for $311 million worth, about $25 for every Illinois resident. Alaska asked this year for earmarks totaling $198 million, about $295 for every Alaska citizen.
Palin has cut back on pork project requests but, under her administration, Alaska is still and by far the largest per-capita consumer of federal pet-project spending.
The governor did reject plans to build the notorious "Bridge to Nowhere" after Congress had cut off its financing.
McCain and Palin were presented as a maverick team in a campaign ad released Monday that played up their reputation for taking on entrenched interests. The ad credits Palin with stopping the bridge without mentioning she once supported it.
In turn, Obama released a response ad accusing the Republican pair of lying about their records.
President Bush, who came to Washington as a former Texas governor without national legislative experience, called Palin "an inspired pick."
"She's had executive experience, and that's what it takes to be a capable person in here in Washington, D.C., in the executive branch," he said in a Fox News interview to be shown Tuesday. In Rome, Vice President Dick Cheney also sought to deflect Democratic criticism that Palin, lacks the gravity to be vice president.
"Each administration is different," he said. "And there's no reason why Sarah Palin can't be a successful vice president in a McCain administration."
In attacking Obama on Monday, McCain said the Illinois senator's earmark total over the years amounts to "almost a million dollars for every single day he was in the United States Senate." McCain doesn't seek pork projects and vows to do away with them as president.
While speaking to voters in Indiana during the weekend, Obama ridiculed the idea of McCain and Palin presenting themselves as reformers, and suggested Palin was distorting her own record on earmarks.
"I know the governor of Alaska has been saying she's change, and that's great," Obama said Saturday. "She's a skillful politician. But, you know, when you've been taking all these earmarks when it's convenient, and then suddenly you're the champion anti-earmark person, that's not change. Come on! I mean, words mean something, you can't just make stuff up."
In a conference call with reporters, Democratic Gov. Ed Rendell of Pennsylvania questioned McCain's assertions that Palin has the necessary experience and record.
"I think she has tremendous potential, but she in no way shape or form is ready to be president of the United States," said Rendell, who knows Palin through the National Governors Association. "And that's something we've got to get across to the American people."
Associated Press writer Peter Jackson in Harrisburg, Pa., contributed to this report.