REPUBLICANS HAVE formally nominated John McCain as their presidential candidate as his campaign stepped up its defence of 44-year-old Alaska governor Sarah Palin as his running mate.
Ahead of Ms Palin's keenly anticipated speech to the party's convention in St Paul last night, the McCain campaign released a television ad claiming that, after less than two years as governor, she is more experienced than Democratic presidential nominee Barack Obama.
"She took on the oil producers. He gave big oil billions in subsidies and giveaways," the ad says. "She's earned a reputation as a reformer. His reputation? Empty words."
Amid reports that Ms Palin was not interviewed by Mr McCain's vetting team until a week ago, the McCain campaign said it was no longer prepared to discuss the process by which she was chosen.
"Senator McCain picked his governing partner after a long and thorough search," senior adviser Steve Schmidt told the Politico, a Washington newspaper.
"The McCain campaign will have no further comment about our long and thorough process. This nonsense is over. It is time to begin the debate about how to win the two wars this country is engaged in, how to make this country energy independent and how to create jobs for American families that are hurting.
"The American people get to do the vetting now on election day," said Mr Schmidt.
A mother of five with a strong anti-abortion, anti- taxation and pro-gun rights record, Ms Palin has energised the Republicans' conservative base, triggering a flood of contributions to the McCain campaign.
But revelations about her 17-year-old daughter's pregnancy, Ms Palin's past association with an Alaskan secessionist party and contradictions in some of her political positions have dominated the headlines in recent days.
McCain supporter Carly Fiorina, a former chief executive of Hewlett Packard, said yesterday that much of the media's criticism of Ms Palin was driven by sexism and warned Democrats that attacks on the Alaska governor could backfire.
"The Democratic Party stood by while Hillary Rodham Clinton was subjected to months of sexist attacks," she said. "The Republican Party is not going to stand by. And millions of American women are not going to stand by either, whether they agree with Sarah Palin or not."