PHILADELPHIA - President Obama concluded a day of fundraising across two states by telling supporters to "pay attention" to what Republican rivals were offering as contrasts to his policies.

"I am telling you, I want you all to pay attention over the next five months and see if they're offering a single thing that they did not try when they were in charge, because you won't see it," he said.

Speaking at this city's Franklin Institute, Obama reminded the crowd of the last Democrat to reside in the White House, Bill Clinton. It was the last time the federal government maintained a budget surplus.

By the time I got into office, we had a $1 trillion deficit because of tax cuts that weren't paid for, two wars that weren't paid for, a prescription drug plan that was not paid for," he said.

"We had baked into the cake structural deficits that were made even worse by the financial crisis," he then said of George W. Bush.

The president tried to draw a parallel with presumptive Republican nominee Mitt Romney's support of a $5 trillion tax cut, saying he could guess at how it would work.

"Either it's not paid for, in which case, that's $5 trillion that's piled on top of the debt we already have, passed onto the next generation," the president began. "Or it's going to come from middle-class families."

About 500 donors crammed under the central rotunda of the Franklin Institute to hear the president. The building is a learning center named for hometown hero Benjamin Franklin.

The president invoked the ingenuity of the founding fathers to paint a picture of American innovation, suggesting that in a second term he would sharpen efforts to push infrastructure, high technology, and environmental projects.

"That's how we became an economic superpower," he said. "So the notion that we would now shortchange our investments in science and basic research, the possible cures for cancer or Alzheimer's, or the clean energy that can make sure that we're doing something about climate change and saving money for families - that's not the answer."

Touting the end of the war in Iraq and progress on gay rights, Obama's statements to the donors were largely in sync with a script he has been using for months.

The appearance in Philadelphia was split into three separate fundraising events that should pull in north of $1.8 million. While tickets for the rotunda remarks started at $250 a piece, to attend a dinner reception afterwards 75 supporters would donate at least $10,000. The bulk of the funds came from a small roundtable discussion of 25 people, paying $40,000 a chair.

Combined with earlier fundraising events in Baltimore, the Obama Victory Fund is expected to raise at least $3.6 million by night's end, according to the campaign.

Not everyone who saw the president in Philadelphia donated money. Before the fundraiser Obama met with about a hundred graduating high school seniors of the Science Leadership Academy, a partnership between the Franklin Institute and the city's public schools.

Congratulating them on their accomplishment, he told the students he was struck by the diversity of the class.

"You guys are representative of the future," he said, "This is a great postcard for what America is all about."