Looking out at a sea of 35,000 people who crammed a downtown park on a chilly day, the Democratic presidential candidate noted blue-collar and manufacturing workers in the audience who waited hours to see him. They face disappearing jobs in this traditionally Republican state which has both a Rust Belt economy and rural areas.
"That's whose president I want to be," he yelled, getting rousing cheers in response.
With stock markets diving, unemployment rising and Indiana alone losing 4,500 jobs in September, Obama argued that the country cannot afford a President McCain who "thinks the economic policies of George W. Bush are just right for America."
"He made kind of a strange argument that the best way to stop companies from shipping jobs overseas is to give more tax cuts to companies that are shipping jobs overseas," Obama said of his opponent. "More tax cuts for job outsourcers. That's what Sen. McCain proposed as his answer to outsourcing."
Over recent days, McCain has kept up a drumbeat of criticisms of Obama's tax plans. He's said the Democrat would hand out "welfare" because even people who pay no taxes would receive a $500 tax credit. He also has said Obama's entire plan amounts to socialistic tax redistribution policies.
Though Obama has appeared to gain an edge in the race for the White House amid the economic turmoil, some polls show McCain could be gaining ground with his aggressive message.
In response, Obama has been devoting more and more of his campaign stump speech to point-by-point rebuttals of McCain's criticisms. He notes his tax proposals would reverse cuts passed during the Bush administration for the wealthiest taxpayers and use the revenue to cut taxes for workers earning less than $250,000 a year. Obama says that means a tax cut for 95 percent of taxpayers. McCain wants to extend all the Bush-era tax cuts, including those for wealthier Americans, and says allowing any to expire would amount to a tax increase.
On Thursday, keeping up a schedule that has had him exclusively in states that voted Republican in 2004, Obama continued defending his plans - but also unleashed a sharp counterattack against McCain over corporate taxes.
McCain proposes cutting the corporate tax rate to 25 percent from 35 percent, while Obama would raise corporate taxes to help pay for tax cuts for everyone earning under $250,000 a year.
Obama referred to comments by McCain in a CNN interview on Wednesday that "it's simple fundamental economics" that American companies would shift operations to other countries with lower tax rates.
"Well, Indiana, my opponent may call that "fundamental economics,"' Obama said, "but we know that's just another name for Wall Street first, Main Street last. That's the kind of economic philosophy we've had for the past eight years and that's just fundamentally wrong."
He went on to say that McCain is wrong on free-trade policies that would "protect the profits of multinational corporations" and on a tax code influenced by corporate lobbyists. "That's the system he wants to preserve," Obama said. "He wants to keep on putting corporations ahead of workers."
Indiana, which has 11 electoral votes, hasn't backed a Democrat for president since 1964. But polls show a tight race between McCain and Obama.
After the rally, Obama was scheduled to fly to Hawaii to see his ailing grandmother, 85-year-old Madelyn Payne Dunham, who helped raise him. Dunham was recently released from the hospital and was said to be gravely ill after breaking a hip.
Obama was to spend Thursday night and most of Friday with her before resuming campaigning Saturday in Nevada.
Obama said the decision to go to Hawaii was easy to make, telling CBS News that he "got there too late" when his mother died of ovarian cancer in 1995 at age 53, and wants now to make sure "that I don't make the same mistake twice."
"My grandmother's the last one left," he told Harry Smith on The Early Show.