President Obama has been looking for new ways to keep pressing the same attack on Mitt Romney’s tax plan, and on Monday, he coined a phrase he hopes will stick: “Romney Hood.”

Ever since a study came out last week suggesting that Mr. Romney’s plan would result in tax increases, not cuts, for the middle class, Mr. Obama has been touting it at every campaign stop. In effect, he argues, Mr. Romney wants to take from the middle class to give more tax cuts to the rich.

“It’s like Robin Hood in reverse – it’s Romney Hood,” Mr. Obama told supporters at a fund-raiser in Stamford, Conn.

Mr. Obama has hammered away at the tax study in the hope of taking ownership of an issue that has long bedeviled Democrats even as he presses Congress to let taxes rise for income over $250,000 a year.

The Romney campaign has disputed the study, by the nonpartisan Tax Policy Center, calling it flawed and biased. The study was based on assumptions about how Mr. Romney would meet his stated tax-cutting goals while not increasing the deficit since he has not filled in all the details himself.

“President Obama recently said the biggest regret of his first term was not telling better stories,” said Ryan Williams, a Romney campaign spokesman. “He’s trying to make up for it now, but his stories just aren’t true. There’s only one candidate in this race who’s going to raise taxes on the American people, and that’s Barack Obama.”

The president’s appearance in Stamford before an expected audience of 500 paying $500 each will be followed later in the evening by a more exclusive dinner at a private home in Westport for 60 donors who paid $35,800 apiece.