MAQUOKETA, Iowa – It was an unusual question at the end of a long day. What, the fifth-grader asked Barack Obama, would you do as president if illegal immigrants staged a terrorist attack on the United States while you were pulling troops out of Iraq?

Without losing sight of his main purpose – convincing the 200 or so adults in the crowd to caucus for him on Jan. 3 – the Democrat responded at length. He promised tougher border enforcement and a crackdown on employers who hire illegal immigrants. He called for compassion for exploited workers. He needled Republican candidate Mitt Romney for talking tough on immigration when, it turns out, illegal immigrants were tending his yard.

He ended by assuring the boy: “I don’t want you to think they’ll be blowing us up any time soon. My job as president will be to make sure that doesn’t happen.”

Obama burst onto the national political scene with a supernova brilliance, thanks to a single, soaring speech he delivered in July 2004 at the Democratic National Convention. His performance as a presidential candidate has not always matched that promise. He can sparkle at one stop and put a crowd to sleep at the next.

But lately, on the stump here in snow-crusted Iowa, Obama has evolved into a more confident, focused candidate than just a few months ago. His message, a call for “real, meaningful change,” is the same it has been for roughly the past year.

The candidate once criticized for lacking specifics now peppers his speeches with policy proposals. The candidate of hope and high ground strikes at Sen. Hillary Rodham Clinton with unspoken allusions – no negative campaigner he – and an occasional sarcastic aside.

It was not an easy transition. Obama’s only previous race was a cake-walk run for the U.S. Senate in Illinois. Even then, he had plenty of time to work out the kinks and, literally, see how things played in Peoria. By contrast, his presidential campaign “started on Broadway opening night,” as Robert Gibbs, a senior Obama adviser put it.

But there is plenty of detail, something that was not true when Obama made his first pass through Iowa.

He calls for public financing of elections and raising the minimum wage to keep pace with inflation. He favors closing the U.S. prison at Guantanamo Bay, and a phased withdrawal of U.S. combat troops from Iraq over 16 months. He proposes giving college students a $4,000-a-year tax credit in exchange for community service, and boosting federal education funding by $18 billion a year to pay for higher teacher salaries.

He wants better early childhood programs and more aid for disabled students.

The specificity impressed Jamey Dirks, 37, a construction manager in Dubuque, who was working at a volunteer sign-up table when Obama appeared Friday morning in Monticello, in northeast Iowa. Dirks, wearing an Obama sticker and a pin with the candidate’s smiling face, became a convert last weekend, when he saw Obama appear in Cedar Rapids alongside Oprah Winfrey.

“There’s real clarity in what he intends to do,” Dirks said. “It’s not like some candidates who just ramble it off.”

That mixture of celebrity and substance has made for a potent combination, helping fuel Obama’s recent momentum in Iowa. Polls have him climbing in what amounts to a three-way contest with Clinton and former Sen. John Edwards of North Carolina. Surveys also show Obama gaining ground in New Hampshire, the state that will vote just five days after Iowa kicks off the 2008 balloting.

In the middle school gym in Olewein on Friday night, Obama cracked wise about an attack from the Clinton camp that cited a kindergarten essay –“I Want to Become President” — as a sign of his overweening ambition. “Let me tell you, when I was in kindergarten I didn’t write essays,” Obama said, drawing laughs from the crowd of about 350 people. “I was smart, I could write my name, “Barack.’ I could write “mom.’ I wasn’t writing essays.”

Winding up a news conference Saturday, Obama was asked how he planned to top Clinton’s intention to skitter across Iowa Sunday by helicopter. He paused. Smiled broadly. “Magic carpet,” he replied.