US President Barack Obama's campaign intensified attacks on Mitt Romney's honesty as it tried to halt the Republican challenger's momentum after a strong first debate performance.
Romney's people on Sunday hit back, and did so sarcastically, depicting Obama's people as childish sore losers after he came across as flat, nervous and unassertive during their first face-to-face encounter in Denver, Colorado.
As both sides gear up for a debate this week between the vice presidential candidates, the race for the November 6 election has degenerated into a testy back-and-forth over who advocates what, and how the other side spins it.
Romney's ideas for rejuvenating a listless economy by getting more money into consumers' wallets include a package of tax cuts that the Obama side says, citing a non-partisan think tank, would amount to $5 trillion over the next 10 years.
At the debate, Obama mentioned the package several times, and that big number. Romney essentially said he did not know what the president was talking about, and insisted any tax cuts he enacted would be offset by closing tax loopholes and ending deductions, so the effect on the deficit would be nil.
Robert Gibbs, a senior Obama strategist, conceded that the former Massachusetts governor did very well at the debate in Denver.
"But the underpinnings and foundations of that performance were fundamentally dishonest," Gibbs said on the ABC program "This Week."
"If you're willing to say anything to get elected president, if you are willing to make up your positions and walk away from them, I think the American people have to understand, how can they trust you if you are elected president?, Gibbs said.
"It's impossible," top Obama campaign adviser David Axelrod said, insisting Romney has failed to name even one such loophole he would shut and that even if he closed all the ones enjoyed by wealthy Americans, he would fall far short of making his plan revenue-neutral.
"He has to sock it to the middle class or explode the deficit," Axelrod said. "This is a shell game. Whichever shell you pick up, the middle class loses."
Obama was on a campaign swing Sunday in Los Angeles, attending a fundraiser at a private residence and speaking at two rallies in the state with the most electoral votes of any.
Romney meanwhile was campaigning in Florida, a battleground state seen as critical to victory in November.
"You all had the chance to hear his answers, or his non-answers," Romney said of Obama as the crowd roared. "Now, of course, days later we are hearing his excuses, and next January we'll be watching him leave the White House for the last time."
The Obama campaign has put out an attack ad about Romney allegedly disavowing his own tax plans entitled simply "Dishonest." On Sunday, Romney's side returned fire with an ad that says Obama "continues to distort" his economic plan.
The new Romney ad features a sound bite from Stephanie Cutter, Obama's deputy campaign manager, telling CNN, "Well, O.K., stipulated, it won't be near $5 trillion."
Romney campaign senior adviser Ed Gillespie said Romney had made a fact-based critique of Obama's handling of the economy, the president could not answer, and now his people are throwing a tantrum.
"They remind me a little bit of a seven-year-old losing a checker game, and then instead of being frustrated at the outcome, they sweep the board off the table," Gillespie said on ABC's "This Week".
Going into the first debate, the 65-year-old Romney was in dire need of a turnaround as a month of campaign misfires and missteps since the Republican party's nominating convention had left him trailing in the opinion polls.
The first surveys since the debate do indicate some kind of bounce for Romney but it is too early to tell how significant or how lasting, especially in the key battleground states that will decide the November 6 election.
Obama's campaign for re-election did get some good news last week, with word that a 2012-campaign record $181 million in donations poured into its war chest in September and the jobless rate fell from 8.1 percent to 7.8 percent.
Romney will come in for further scrutiny on Monday when he gives a major address on foreign policy.