Over the weekend, while U.S. Sen. Barack Obama campaigned for president in Iowa with his family, one of his daughters had a question.

"Why are we here again?" Obama said, recounting the question his 8-year-old daughter Malia posed to a family member.

It's a question Obama answered Sunday for a roaring crowd of more than 7,000 people who welcomed him home with a rally at the University of Illinois at Chicago arena.

"Maybe every two years or four years, you hold your nose and you go in and you vote for what you consider to be the lesser of two evils, but you don't have confidence that politics is going to make a real difference in your life," he told the crowd.

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So Obama told them, the answer to his daughter's question was this: "That's got to change."

Sunday was the second working day of Obama's campaign after the pomp and circumstance of Saturday's announcement in Springfield that he was running for president.

Obama came home for the Chicago rally after spending the morning in Iowa, a key state for any presidential candidate because of its leadoff caucuses. The visit home for Obama also included a Sunday night fundraiser.

He has scheduled appearances in New Hampshire on Monday, another important stop because that state traditionally hosts the country's first primary.

In the meantime, Obama got to bask in the friendliness of his home state, but he didn't let all the attention go to his head.

"I am an imperfect vessel for your hopes and dreams," Obama told the raucous rally crowd.

Barb Vina of Roselle doesn't think of that him way.

"I love all of his message," Vina said after the event, where Obama reiterated the themes of his announcement address, including how to extract the United States from the war in Iraq and making sure everyone in the country has health insurance.

Obama's weekend events have drawn thousands of people, starting with the more than 15,000 people who stood outside in frigid temperatures in Illinois' capital city to hear him announce his presidential bid.

Earlier Sunday, Obama spoke to thousands at Iowa State University and met with party activists at a private home in Iowa Falls.

In Chicago, Obama's speech was interrupted several times by a group of chanting protesters in the audience with a sign calling on Obama to "Stand up! Cut the funding," presumably for the war in Iraq.

"Hey guys, come on ... you made your point," he told the protesters who were booed by the audience.

Obama, who had been talking about health care, told them he would get to their issue about the war soon, but they were escorted out before he got to it.

"We have a responsibility to be as careful coming out as we were careless getting in," Obama said of the American presence in Iraq.

Rob Biederman of Niles, who came to the rally with his 5-year-old son, said Obama's candidacy for president is the start of a movement.

"It's the idea that he represents hope," Biederman said.

But college student Ashley Thomas, who was waiting outside the rally site three hours before Obama was scheduled to speak, knows it won't be an easy road for him.

A crowded field of candidates is after the Democratic nomination, including fellow senator and former first lady Hillary Clinton.

"That kind of scares me," Thomas said.

She said she also worries Obama's years of experience are another hurdle he will have to overcome. Obama is a first term U.S. senator who was elected in 2004. Before that, Obama was a state senator representing Chicago's South Side.

Still, Thomas, 19, is pumped up to work for him: "Whatever they want me to do," she said.

Eileen McKeough, 41, of Chicago, isn't concerned about Obama's level of political experience.

"He's incredibly smart," McKeough said.

Observers say Obama was wise to start laying the groundwork for his presidential run by immediately going to Iowa after announcing his candidacy.

"The more face time you get in Iowa the sooner, the better — and the same in New Hampshire," said James Nowlan, a senior fellow at the University of Illinois' Institute of Government and Public Affairs.

After attending Sunday's Chicago rally with his wife, Michelle, the couple headlined a fundraiser at a downtown hotel, where supporters gave from $500 to $2,300.

"I need your money, I need your time, I need your energy," Obama told the crowd.

Rob Warden, director of Northwestern University's Center on Wrongful Convictions, said about 750 people attended the event. It was not immediately known how much money was raised.

"He is a person of such tremendous substance, it's a tremendous honor to be able to support him," Warden said.

Chicago Public School CEO Arne Duncan and State Treasurer Alexi Giannoulias were among the people attending the event.

The hectic pace Obama is setting with his new campaign is expected to get more harried.

"This is the first step in a long, long journey," said Obama political strategist David Axelrod. "The most important thing he needs to do is let people get to know him more than they know him now, understand what his life has been about, understand what his history has been."

Obama, elected to the U.S. Senate in 2004, shot up the political celebrity ladder that year after delivering a major speech at the Democratic National Convention. He also authored two best-selling books, appeared on the cover of several major magazines and has been profiled on several television shows.