Mrs. and Mr. Anne Romney
Mrs. and Mr. Anne RomneyReuters

Mitt Romney's wife is reinforcing her husband's refusal to make public more of his of tax returns, saying "we've given all that people need to know" about the family's finances.

Ann Romney told ABC News she thinks the Obama campaign's attacks on her husband have been "beneath the dignity of the presidency." And she says people will decide whom to vote for based on whether their lives would be better under Mitt Romney than President Barack Obama.

She says she believes voters are "going to fire the coach."

Ann Romney says the family gives 10 percent of its income to the Mormon church and he took no salary during his four years as Massachusetts governor. She says that should be enough to put aside people's concerns about his finances.

Romney released tax information from 2010 and 2011 earlier this year when Republican primary opponents accused him of paying less than ordinary Americans.

However, weeks of attacks by Obama about his taxes and business past are preventing Romney from focusing voters' minds on the White House's handling of the weak economy.

Her remarks come as some senior Republicans worry that Romney is becoming boxed in by the Obama team, just at the time in the race when many Americans begin to tune in and form clearer opinions about candidates before the Nov. 6 election.

But a New York Times/CBS News poll of 982 registered voters between July 11 and 16 showed support for Obama's handling of the economy taking a noticeable hit. 

Only 39 percent of respondents backed the president on the issue compared with 55 percent who did not. A similar survey in April showed 44 percent behind Obama on the economy, with 48 percent of respondents unhappy with his performance.

That shift, combined with Romney now raising significantly more funds for his presidential bid than Obama, means Romney has - even before the Republican convention - become a contender.

Anne Romney's remarks in defense of her husband were likely attended to free the GOP challenger to go on the offensive and make the most of Obama's weak economic credentials.

On Wednesday, Romney accused Obama of demonizing business success, as the Republican tried to ignore questions about his personal finances that threaten to damage his presidential bid.

"This idea of criticizing and attacking success, of demonizing those in all walks of life who have been successful is so foreign to us we simply don't understand it," Romney told a townhall-style meeting.