SOMERSET, Pa. - Former Pennsylvania U.S. Sen. Rick Santorum formally kicked off his campaign for president Monday, offering himself as a tested leader with the "courage to fight for freedom . . . to fight for America" against an expanding social-welfare state centered in Washington.

He spoke from the steps of the Somerset County Courthouse, flanked by his wife, Karen and seven children, with several hundred followers packed in amid balloons, flags and a jazz band - an old fashioned political rally from an earlier time, before politicians announced for president on Facebook and Twitter.

President Obama has "devalued our currency and devalued our culture," Santorum said, faulting the president for mismanaging the economy and declining to uphold in court the Defense of Marriage Act, which allows states to refuse to recognize gay marriages.

A former two-term senator who lost his seat in 2006 to Democrat Bob Casey by 18 percentage points, Santorum has been most known in his career as a leader of social-issues conservatives, but the case he built against Obama was mostly economic and spiritual, in the sense that, as he portrayed, the increased reliance of citizens on government threatens the national character.

He said the president has spent recklessly, with a federal stimulus aimed mostly at keeping government workers on the payroll, to keep power. Obama, Santorum said, has fretted over high gas prices while limiting domestic exploration for new oil supplies.

Obama has "wrecked the economy, centralized power in Washington, D.C. and robbed people of their freedom," Santorum said. Although Obama was elected in 2008 asking voters to believe in him, it is more important for Americans to have a president who "believes in them," Santorum said.

Santorum chose Somerset because his grandfather, Pietro, worked as a coal miner in nearby Carpenter's Park in 1927 after emigrating from Italy. Pietro had a comfortable life as a government functionary under the Mussolini regime, Santorum said, but came to the U.S. for freedom.

"That is the American we need again," Santorum said.

He reserved special scorn for Obama's health-care overhaul, which Republicans call "Obamacare." It is vital to repeal that program, he said.

"They want to hook you, they don't want you to be free," Santorum said, of the administration. "They believe in themselves, the 'smart' people, the planners in Washington . . . the people who can make decisions better than you."

So far, Santorum has languished in the single digits in polls of the Republican race, but he has made more trips to Iowa, New Hampshire and South Carolina than other candidates and is seen as having an opening to consolidate evangelical voters behind him, now that former Arkansas Gov. Mike Huckabee, a Baptist minister, has decided not to run. Of course Santorum, a Roman Catholic, could face competition from possible candidates Sarah Palin and Rep. Michelle Bachmann of Minnesota.

"We had a great reception and we're going to keep going," Santorum told reporters as he was hustling to a series of media appearances and a flight to Iowa.

Contact politics writer Thomas Fitzgerald at 215-854-2718 or tfitzgerald@phillynews.com. Read his blog The Big Tent at philly.com/BigTent.