Obama has been in the Pennsylvania, also known as the Keystone State, campaigning all weekend. He is expected to share the state with his rival, Sen. Hillary Rodham Clinton, beginning Monday.
Obama says he introduced himself to Pennsylvanians with a retail campaign that, like in Iowa, got him out to where the voters live. At the agricultural center at Pennsylvania State University, Obama played nurse-maid to a one-month-old calf.
"I need a shot of this for my 9 and 6-year-olds," he told photographers. "Every day, they Say, 'What did you do today?' I say, 'Well, I gave speeches.' [They say] 'Boring.'"
At dinner, the senator ordered hot dogs and French fries, then went bowling with Pennsylvania state Sen. Bob Casey, where, like all bowlers, he tried to avoid the gutter but could not.
Obama has strong support in Philadelphia but has a big challenge overcoming Hillary Clinton's double-digit lead in the diverse state.
That lead is something Senator Clinton wants to protect as she returns to Pennsylvania Monday, after she and her campaign fended off calls to get out of the race.
"Chill out," former President Bill Clinton told a crowd gathered over the weekend. "We will win this election if we just chill out and let everyone have their say."
"There some who say that we should stop this. I don't know where that comes from. It's March," Senator Clinton said.
The Democratic party fears all the fighting is only helping Republican John McCain. The presumptive GOP nominee, however, is watching what is happening with the fighting in southern Iraq, knowing that as that conflict goes, so likely do his electoral prospects.
In the past week, starting in Meridian, Mississippi, McCain embarked on a "Service to America" tour, visiting the places that have figured prominently in his life.
"Each one of the places we're going to was part of the formative experiences that shaped my views and my thinking," McCain said.