By Margaret Chadbourn
STAMFORD, Connecticut (Reuters) - Adding a new attack line to his campaign arsenal, President Barack Obama derided Republican rival Mitt Romney's tax plan on Monday as Robin Hood in reverse - "Romney Hood " - saying it essentially would rob ordinary Americans to help the rich.
Obama stepped up his criticism of Romney's tax proposals at a re-election fundraiser in Connecticut on the same day Romney's campaign reported that it had outraised the Democratic president by more than $25 million in July.
Reaching back to the Middle Ages, Obama invoked the legendary outlaw of old in an attempt to sharpen the contrast with Romney, whom the president said would cut taxes for the richest 2 percent of Americans and pay for it by raising taxes on the middle class.
"It's like Robin Hood in reverse. It's Romney Hood," he said, drawing loud applause and laughs from a crowd of about 500 who paid $500 a head to attend the event in a hotel ballroom.
It was the latest twist in the Obama campaign's effort to paint Obama as a champion of the middle class while casting Romney, one of the richest men to ever run for the White House, as intent on protecting the fortunes of wealthier Americans.
Obama sought to back his accusation by citing a report last week by the nonpartisan Tax Policy Center that found that Romney's proposal to slash income taxes by 20 percent across the board would boost income for the wealthiest taxpayers while reducing it for lesser earners.
The study calculated that Romney's tax cuts would boost after-tax income by an average of 4.1 percent for those earning more than $1 million a year, while reducing by an average of 1.2 percent the after-tax income of individuals earning less than $200,000.
The Romney campaign called the study biased.
Romney campaign spokesman Ryan Williams, responding to Obama's latest accusations, said the president was the only one in the race who would raise Americans' taxes.
"While he's used taxpayer dollars to grow government and reward his donors, middle-class Americans have seen fewer jobs, lower incomes, and less hope for the future," he said.
When Obama later headlined a glitzier fundraiser with a few dozen well-heeled donors at the Westport waterfront home of movie mogul Harvey Weinstein, there was no mention of the Robin Hood analogy in remarks that journalists were allowed to hear.
The $35,800-a-person event was co-hosted by screenwriter Aaron Sorkin and actress Anne Hathaway. Vogue editor Anna Wintour, actress Joanne Woodward and talk-show host Jerry Springer were also in the crowd.
(Writing by Matt Spetalnick; Editing by Stacey Joyce)