ST PAUL, Minnesota, (AFP) - Republican vice-presidential pick Sarah Palin lashed out at Barack Obama Wednesday and styled herself as a scourge of the Washington elite in her high-stakes convention debut. The Alaska governor, in the most important speech yet to the party bonanza that will nominate John McCain, defended her credentials to serve as vice-president, saying she was steeped in executive leadership experience. "Here's how I look at the choice Americans face in this election," the 44-year-old mother of five said in excerpts of her intensely anticipated address, the highlight of day three at the convention. "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." The speech represented a key moment in a Republican bid to quell a personal and political storm raging around Palin, which led Democrats to question McCain's judgment and the extent to which he vetted his shock choice. Palin also painted herself as an outsider, primed to go to Washington to launch a wave of reform, in line with McCain's narrative that he is a maverick reformer. "I'm not a member of the permanent political establishment and 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. "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." Palin also noted she had served as a smalltown mayor in her native Alaska, saying in another swipe at Obama that the job was like being a community organiser "except that you have actual responsibilities." Obama got his start in politics as a community organiser in Chicago after law school. Republicans were sure to give Palin a rapturous reception, but she has a tougher job to court millions of voters watching on television after her rocky rollout as McCain's running mate. "Governor Palin represents a new generation," said former New York mayor Rudolph Giuliani, describing McCain as a "true American hero." "Governor Palin represents a new generation - she's already one of the most successful governors in America - and the most popular. "She already has more executive experience than the entire Democratic ticket. She's led a city and a state." But just before Palin was due to speak, new revelations about her past made headlines, as it emerged she had told ministry students in Alaska in June that US troops in Iraq were sent on a "task that is from God." Another former Republican presidential candidate, Mike Huckabee, meanwhile lashed out at Obama's foreign policy. "Maybe the most dangerous threat of an Obama presidency is that he would continue to give madmen the benefit of the doubt," Huckabee said. "If he's wrong just once, we will pay a heavy price." Palin's speech comes amid signs of rising political pressure on McCain as a new poll in battleground states Iowa and Minnesota showed Obama pulling out a wide lead with only two months to go to the November 4 election. In the bellwether state of Ohio, the race was a statistical dead heat " more bad news for McCain, as no Republican has ever lost there and gone on to win the White House. A new CNN-Time poll showed Obama leading McCain 55pc to 40pc in Iowa and 53pc to 41pc in Minnesota. In Ohio, the race was a statistical dead heat, with Obama, who appears to have grabbed a significant polling bounce from his convention last week in Denver, up by just 47pc to 45pc.