Santorum, at times using a confessional tone, said he and others sometimes have looked at the issues and decided they're too large to tackle.
"That's not why you're here," Santorum said. "That's not why you answered this call. You're here because you're different."
Santorum was introduced by Ralph Reed, the former leader of the Christian Coalition who is working on a comeback after being snared in a Republican lobbyist scandal in Washington. Reed noted that President Obama won Iowa in the 2008 general election by 110,000 votes.
"I say that frankly to our collective shame," said Reed, rallying the crowd to oppose Obama, Democrats and moderate Republicans. "To tell the truth, that election was like a Harlem Globetrotters game and we were the team that showed up to get beat."
Steve Scheffler, a GOP national committee member and president of the Iowa Christian Alliance, said the group had invited Santorum because "he's a guy who supports our issues."
The alliance hopes to lure other prospective Republican presidential candidates to speak. Scheffler said he could not predict how Santorum would fit into that field.
"I think it's way too early to tell," he said. "I think it's a wide-open field."
The Iowa caucuses in January 2012 serve as the starting line of the marathon primary-election campaigns necessary to win the nomination to run for president.
Santorum in January sent a letter to voters nationwide who had contributed to his political-action committee, America's Foundation, telling them he was "actively considering" a run for president in 2012.
