is on," Perry said. "A renewed nation needs a new president."

Perry recited a litany of issues facing America, including debt, high unemployment and hefty energy costs. Leadership under Obama, he said, is "rudderless."

"It's time to believe the promise of our future is better than the best days behind us," Perry said to applause.

He launched his presidential campaign website, rickperry.org, shortly before the announcement.

The timing of the announcement buttressed Perry's bid to get attention on a busy day in American politics: His South Carolina speech started the same hour as those given by candidates making a pitch for straw poll votes in Iowa.

Merle Black, a political science professor at Emory University in Atlanta, said Perry's appeal to both social and fiscal conservatives could be crucial in the South CarolinaRepublican primary, which every GOP presidential nominee has won since 1980.

"He would appeal to tea party Republicans, he would appeal to the individuals who are interested in job creation in the state," Black told CNN. "He can also, I think, appeal to evangelical Christians, and the overlap between evangelical tea party Republicans, economic development Republicans -- those are a lot of voters in a South Carolina Republican primary."

South Carolina Gov. Nikki Haley helped kick off the RedState conference, saying Republicans will unite to defeat Obama.

Perry told the South Carolina crowd that he has helped cut taxes and government spending in Texas.

Meanwhile, Obama campaign spokesman Ben LaBolt struck back, saying Perry "pledged to support the 'cut, cap and balance' plan that would preserve subsidies for oil and gas companies