New figures show Obama and his allies raised nearly $85 million in August, outpacing Romney's haul in the month that included both parties' national conventions.
In Wisconsin, conservative candidate Tommy Thompson put some of the blame for his slipping poll numbers on the Romney campaign and conservative commentators, including former GOP speechwriter Peggy Noonan, have depicted the Romney team as floundering.
"Stop it. This is hard. You want to try it? Get in the ring," Ann Romney said of her husband's critics in an interview on Thursday with Radio Iowa.
Romney tweaked his campaign strategy twice this week in response to controversies that distracted from his main message challenging Obama's record as president.
On Thursday, he kept up attacks on Obama over a 1998 comment regarding redistribution of wealth, and also claimed the president had given up on changing Washington. The Obama camp fired back that the criticism was off base.
At the AARP event Friday, Obama said the Ryan proposal to reform Medicare would make it a voucher program that shifts health care costs to senior citizens. He noted that AARP supported the 2010 health care reform act and opposed Ryan's Medicare proposal.
"They know that a voucher program is not going to be a good deal," Obama said.
Ryan, however, denied it was a voucher program and insisted that the idea originated in Democratic proposals of the past.
"This financial support system is designed to guarantee that seniors can always afford Medicare coverage -- no exceptions," he said to some applause.
Members of AARP -- a nonprofit organization and a powerful lobbying group that boasts of having more than 37 million members -- submitted questions to the nominees on their website.
Tough stretch for Romney
Romney is coming off a tough stretch in the weeks before the three presidential debates in October.
Last week, the Romney campaign struggled in its initial response to anti-American violence in Libya and Egypt. Then a left-leaning magazine released secretly recorded clips of Romney speaking at a May fund-raiser in which he said 47% of Americans depended on government help, saw themselves as victims and won't support him.
Under criticism for the comments at the fund-raiser, Romney stuck by them and rallied some conservative commentators to his side by emphasizing his message on his allegation that Obama's polices increased public dependency on government.
In particular, they accused Obama of favoring wealth redistribution -- code for socialism among conservatives -- based on the 1998 video of the president when he was a state senator in Illinois.
"I think the trick is figuring out how do we structure government systems that pool resources and hence facilitate some redistribution -- because I actually believe in some redistribution, at least at a certain level to make sure that everybody's got a shot," Obama says in the clip, posted Tuesday on the conservative Drudge Report website.
The White House on Wednesday characterized the GOP attacks over the redistribution comment as an effort to divert attention from Romney's remarks at the May fundraiser.
Romney also took aim at Obama's comment on Thursday at a Univision "Meet the Candidates" forum in which the president said he was unable to change Washington from within.
House Speaker John Boehner continued the Romney attack line on Friday, saying Obama and congressional Democrats lacked the leadership qualities necessary to change the culture of partisan divide and legislative gridlock.
"It takes courage, it takes determination and it takes sincerity, and it's called leadership," Boehner told reporters.
Asked about the inability to work out compromises with Republicans on deficit reduction and other major issues, Obama blamed GOP intransigence and said he was being a leader by rejecting what he called "bad ideas."
He noted that his proposals, including the health care reform measure opposed by every Republican, included some ideas with GOP origins.
"Obamacare owes a debt to what was done in Massachusetts by my opponent, Mr. Romney, even though sometimes he denies it," the president said in a jab at his challenger, who passed a similar plan while governor of the state but now vows to repeal the federal version.
"The one thing I won't do though is go along with bad ideas that are not helping the middle class," Obama said to applause, adding: "If I hear the only way Republicans in Congress are willing to move forward is to voucherize Medicare, I'll say no."