Obama, the junior United States senator from Illinois, spoke for about 45 minutes to more than 4,000 people — many of them University of Wisconsin students — at Madison's Monona Terrace.
Reaching out in particular to young people in the audience, Obama shared his vision of the nation.
"I see a core decency in the American people — a generosity of spirit between people," Obama said. "I see that in all of you — so many young people who are waiting once again to be inspired to do something outside of themselves, to work on behalf of something much larger."
Obama said the partisan bickering in Washington right now is discouraging for the American people.
"People want to believe that politics can be something uplifting, that it can provide a sense of mission … to make the country all it can be," Obama said.
The senator, considered one of the leading Democratic candidates in the race for the White House, addressed criticism that he has not spent enough time in the nation's capitol to become president by saying he can provide the inspiration and leadership he believes the country needs.
"Dick Cheney and Donald Rumsfeld have two of the longest résumés in Washington, and they led us into the biggest foreign policy disaster in a generation," Obama said. "So a long résumé does not guarantee longevity. Longevity says nothing about your character."
Obama spent time blasting President Bush's administration, saying the nation is "tired" of the president and many of his cabinet members.
"This administration has treated our Constitution as an annoyance, to be avoided, as opposed to a foundation of our liberty," Obama said.
However, Obama said it is important for people to focus their support on one particular candidate, instead of being distracted by their anger toward one political party.
Citing his roles in state government in Illinois, Obama said he stood up against special interest groups and against popular support for the war in 2002 when he was running for the U.S. Senate.
In addition to the war, Obama criticized the Bush administration for their handling of Hurricane Katrina's aftermath.
"People are frustrated by the administration … who leave our fellow citizens standing on rooftops after a storm without water and without food," Obama said.
Gus Doyle, the son of Wisconsin Democratic Gov. Jim Doyle, formally introduced Obama at Monday's event.
"There's a movement," Doyle said. "Opportunities like this do not come all the time to elect a true champion of humanity."
Obama was interrupted a couple times throughout the course of his speech, as at least three people became lightheaded and required medical attention. The senator paused to make sure everyone was OK.
"I'm just knockin' them off their feet," Obama said.
Students paid $15 and the general public paid $30 to see Obama's event, which was moved to Monona Terrace from the Orpheum Theater to accommodate the large crowd.
Obama became the first major candidate to visit Madison leading up to primary elections in early 2008. Democrat John Edwards visited Milwaukee earlier this month and Republican Rudy Giuliani is hosting a private luncheon there Thursday.