"It's like Robin Hood in reverse," the left-leaning Democrat quipped at a campaign event in August. "It's Romney-hood."
Obama took aim at the former Massachusetts governor's promise to cut federal income tax rates by 20%.
Romney would make up for the loss in revenues by eliminating a myriad of tax breaks in the 5–296-page tax code – including perhaps the most coveted deduction of home mortgage interest costs.
Obama charges that the Romney plan would cost middle-class taxpayers another $2 000 a year in lost tax breaks while putting up to $250 000 into pockets of high income people.
Republicans dismiss Obama's arguments as European-socialist class warfare red meat for their conservative supporters. Yet both Romney and Obama claim their main priority in the election is defending the fast-eroding middle class.
In fact, the American middle class has rarely been worse off than since the recent Great Recession. Median household income, adjusted for inflation, dropped 6% to $59 127 in 2010 from $63 277 in 2000, according to the Pew Research Centre.
Meanwhile, the highest income groups flourished. From 1979 to 2007, the top 10% of households by income claimed the lion's share of total income growth – 63.1%, according to the left-leaning Economic Policy Institute (EPI). The bottom 90% saw only 36.9% of the country's income growth.
Supporters of across-the-board tax cuts – including for the highest earners – argue that they "unleash growth" from which everyone will profit, said EPI president Lawrence Mishel. But just the opposite has happened.
Both Romney and Obama concede the urgent need to reduce the federal budget deficit and bring down the $16-trillion national debt.
But Romney opposes any increase in federal income taxes, and aims to cut government entitlement programmes, which could include medical care for the poor and elderly and money for family planning.
Obama is calling for both budget cuts and higher taxation on the nation's wealthiest, whose top tax rate has shrunk from about 90% in the 1950s to 35% on earned income and less on capital gains.
Romney himself, for example, has paid as little as 13% on income from his fortune of over $200-million.
The United States is one of the least-taxed developed countries, ranking third from bottom above Chile and Mexico among Organisation for Economic Cooperation and Development members.
Obama's bid to more heavily tax the rich is backed by majorities of more than 60% in opinion polls, and above 70% even among the more wealthy.
Eric Schoenberg, who inherited wealth from his father and had a successful career on Wall Street, is a member of the Responsible Wealth movement. He told dpa that the wealthy should be more willing to pay into the public sector – if for no other reason than preventing social unrest.
"If this problem is not solved, you will see real confiscation of wealth," he warned.
How is it, then, that US voters have tolerated such wealth inequality amid persistent high unemployment and stagnant income?
Jim Steele, Pulitzer-prize winning co-author of the book Betrayal of the American Dream, said that people "are not very knowledgeable about taxes".
"I think people are riled up about it, angry about it, but it can't seem to get translated permanently into the kind of changes that are necessary," Steele told dpa.
Unless Obama's Democrats regain control of the lower House of Representatives and increases their Senate majority on November 6, even if Obama wins, "nothing will happen," Steele said.
For some tax and fiscal analysts, voters are resigned to a system that has largely been manipulated by wealthy lobbyists and conservative Washington think tanks.
"People are … upset that Mitt Romney pays so little," Bob McIntyre of the left-wing group Citizens for Tax Justice said. "They're not sure that who you vote for will make a difference."
He noted that issues other than taxes drive elections, such as social issues like abortion.
Alan Viard, a tax expert with the conservative American Enterprise Institute, noted that Republican George W Bush campaigned in 2000 on the promise of tax cuts – instead of working to pay down the then $5.6-trillion debt. He won, and his tax cuts are still on the books. – Sapa-dpa