ABC NEWS

By Jake Tapper and Shushannah Walshe

URBANDALE, IOWA - The man riding a surge of support in Iowa, former Pennsylvania senator Rick Santorum, ended his day with a lecture to students at Des Moines Christian School, followed by a prayer.

The event began with the national anthem, sung by some of the Duggar children from the reality TV show on TLC "19 Kids and Counting" - formerly "17 Kids and Counting" and "18 Kids and Counting." Santorum delivered a civics lecture of sorts to the high school students and their parents, extolling the virtues of marriage and criticizing national leaders for not doing so.

"Why wouldn't leaders in this country stand up and promote marriage?" he asked parents and students at the school, which says it offers students "an excellent biblically-directed, Christ-centered education."

"Stop in any way they could the sexual promiscuity that goes on that leads to out -of-wedlock births?" he continued. "Why wouldn't they educate for those things? Why wouldn't they promote traditional marriage of a man and woman instead of trying to break it down?"

But Santorum may have been applauded most heartily when he lectured President Obama.

"If your teacher asks you for your homework assignment and you routinely say, 'It was really hard' … your teacher would say, 'F. Sorry. Incomplete. No good.' Well, that's the routine of this administration, handing in their assignment incomplete and blaming somebody else for the problem."

Santorum said, "To the best of my ability, if I'm elected president of the United States, I will not say the word 'Barack Obama' other than doing so in a respectful and positive way, but I will not say the word 'Barack Obama' to blame for anything that we have not been able to accomplish in our administration. When you run for president, you take responsibility. If there's one lesson you can teach every child looking up to you as president, as I hope they would do, it's that you take responsibility for your actions. If you want to be president, man up and be president."

The crowd included conservative activists Ralph Reed and David Bossie, who came as curious onlookers, as well as billionaire Foster Friess, a longtime supporter. But despite such conservative luminaries in attendance, the event offered a low-key way for Santorum to end what has been a spectacular week for his campaign.

"We went from five [percent in Iowa polls] to who-knows-where we are going to end up in literally less than a week," Santorum told ABC News after the event. "The CNN poll was published last Wednesday, a week before the caucus and that put us, I think, at 16 and we will see where we go from there. But we feel like we will do better than that, hopefully a little better than that, maybe a lot better than that."

Saturday night's Des Moines Register poll brought Santorum even better news. He was solidly in third place, and if one looked at just the final two days of the four-day poll, he was tracking in second place. He clearly was surging. Crowds packed pizza joints to hear him speak. A media scrum following him at an event earlier today looked like a paparazzi beast devouring Lindsay Lohan.

Yet today Santorum seemed quite mellow.

"This is the first step, this is the first step," he told ABC News. "A win here is a start, but it's a start. It's not the culmination, it's a start. It's not the culmination, it's the beginning."

The culmination - both tonight and beyond - depends on whether Santorum will be able to expand his appeal beyond Christian conservatives. Santorum says he's up to the task.

"Look what I did in Pennsylvania for a lot of years," he told ABC News. "In the congressional districts I ran, they weren't Christian Conservative districts. They were blue collar, Catholic, heavily Democratic areas. I got a lot of votes from those folks and the campaign I'm running and the kind of plans I'm working on and my economic plans, manufacturing. It's a pretty good place to go if you are going to go to Pittsburgh or Detroit or places like that when you need to get votes in those states and we think we can do that."

He'll need to move fast. The New Hampshire primary is in just one week.

"Later this week there will be some polls in New Hampshire and we think we will do very, very well in those polls after our showing here and we will be on the upswing there too," Santorum said. "Mitt Romney [has] been up there six years campaigning and living up there, so obviously the expectation is a little different than coming in a week's time going from five to whatever."