Former US senator Rick Santorum Monday officially launched his long-shot bid for the White House, exhorting Americans to "join the fight" to oust Democratic President Barack Obama in 2012.
Blasting the president for his handling of the faltering US economy, the Republican Pennsylvanian also said Obama has "devalued our culture" through social policies such as abortion rights and gay marriage.
The 53-year-old father of seven has scored some success in straw polls in the early primary states, but trails in an increasingly crowded pack of Republican contenders.
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"Fellow Americans, it is our watch, it is our time," Santorum told a cheering rally in Somerset, Pennsylvania, close to where his grandfather settled after immigrating from Italy.
"I'm ready to lead. I'm ready to do what has to be done for the next generation, with the courage to fight for freedom, with the courage to fight for America. That's why I'm announcing today that I'm running for president of the United States," he said.
Santorum's speech lost momentum halfway through when a supporter appeared to faint. But he stepped off the podium to help as the person was carried away for medical attention, before resuming his address.
Santorum attacked Obama for what he called the president's failed policies, a lack of faith in the American people, a devalued "moral currency," and for failing to get a handle on the country's soaring debt crisis.
"Who are you, Mr. President, to say that you and your administration should take 40 cents out of every dollar and borrow it from future generations to prop you up?" Santorum said.
"He's not just devalued our currency, he's devalued our culture, through not standing up for the defense of marriage act, through federal funding of abortions," he added.
Earlier Santorum appeared to acknowledge the improbable nature of his campaign to win the party's nomination, which will see him battle at least half a dozen other Republicans many of whom have higher national profiles.
"If you look back at what I did and when I did it, people can say... 'well he may have lost but he didn't flinch, he stood by what he believed in and he continued the fight to the end,'" Santorum told the ABC network, referring to his 2006 loss to a Democrat of a Senate seat he had held since 1995.
Despite the growing field of Republican candidates including front-runners former governors Mitt Romney and Tim Pawlenty, several prominent conservatives are still weighing a run, including 2008 vice presidential nominee Sarah Palin.
Congresswoman Michele Bachmann, a Tea Party favorite, may be an alternative standard bearer for the fiscal and religious right, while Obama's former ambassador to China Jon Huntsman is also considering a bid.
Long-shot candidates include Newt Gingrich, a former Republican House speaker whose campaign has had a poor start. Even former New York mayor Rudy Giuliani is taking a look -- despite his dismal 2008 campaign.
