Speaking to several thousand people in Indianapolis, Obama acknowledged public anxiety over the financial crisis in starker terms than usual.
Calling it "a moment of great uncertainty for America," he said, "It's harder to make the mortgage or fill up your gas tank." Some people fear losing their electricity because of unpaid bills, he said.
"But this isn't a time for fear or panic," Obama said. "This is a time for resolve and leadership. I know that we can steer ourselves out of this crisis."
Obama ridiculed his Republican opponent,, for recently saying "the fundamentals of our economy are strong." But in his 35-minute speech on a muddy harness-racing track, he made a similar argument.
"America still has the most talented, most productive workers of any country on Earth," he said. "We're still the home to innovation and technology, colleges and universities that are the envy of the world. Some of the biggest ideas in history have come from our small businesses and our research facilities."
Obama repeated his claims that McCain's proposals would cause many Americans to lose their employer-provided health insurance because the Republican would tax those benefits. He said the $5,000 tax credit McCain would give people would not be enough for them to buy private insurance, a claim that McCain disputes.
"The American people can't take four more years of John McCain's George Bush policies," Obama said to loud cheers.
Indiana is normally a solidly Republican state at the presidential level, but polls here show the contest to be close.