Mitt Romney painted a dark vision of a second Obama term on Sunday, telling more than 10,000 supporters at a rally here that the president would raise taxes on the middle class, weaken the military and explode the deficit if reelected.

“I don’t want four more years like the last four years,” Romney, speaking in a rapid-fire tone as rain threatened from a gray sky, said to chants of “USA! USA!”

Before a boisterous crowd spread out on a grassy field next to the town square, Romney tried to capitalize on his momentum from his widely praised debate performance Wednesday.

“We had a little debate earlier this week, and I enjoyed myself,” he said, adding that President Obama has been making excuses for his own performance ever since. “Now of course, days later, we’re hearing his excuses, and next January, we’ll be watching him leave the White House for the last time,” Romney said.

He also expressed confidence that he would capture this critical state and its 29 electoral votes, saying to loud cheers, “We’re going to win in Florida, and we’re going to take back the White House.’’

After his 20-minute speech, Romney walked across the street to the Tin Fish restaurant, where the owner said he and his wife, Ann, were picking up grilled fish and chicken. The cash register was adorned with two Romney-Ryan stickers, and the Republican elephant symbol dangled from strings just behind the counter.

Meanwhile, Obama had no public appearances Sunday but held two fundraisers in Los Angeles.

Addressing a raucous crowd at the Nokia Theatre, Obama continued in the same combative voice he has employed since last week’s debate, also offering a bit of self-deprecating reflection on a performance widely described as listless and uninspired. Praising the night’s musical acts, including Stevie Wonder and Katy Perry, he said: “These guys perform flawlessly night after night. I can’t always say the same.”

Later, Obama acknowledged — without offering specifics — that he and his administration had made missteps.

“We made some mistakes,” he said. “We goofed up. I goofed up. But the American people carried us forward.”

Obama continued to assail Romney’s tax plan as one that would increase the deficit by $5 trillion. He also ridiculed one of the specific cuts Romney offered at the debate, eliminating funding for PBS.

“Don’t worry — someone is finally cracking down on Big Bird,” he said. “Elmo has made a run for the border.”

Obama began his evening with a small group of longtime donors at the home of entertainment mogul Jeffrey Katzenberg, where Obama was joined by former president Bill Clinton. His campaign called the gathering a “thank-you event.”

The president wrapped up his night at Wolfgang Puck’s WP24 restaurant, on the 24th floor of the Ritz-Carlton hotel in downtown Los Angeles. With 150 people expected at a cost of $25,000 per person, that event alone could have raised $3.75 million.

Obama’s fundraising efforts were a topic on the Sunday political talk shows. On Saturday, the campaign announced it had raised $181 million in September, a near-record haul that pushed the overall total for the campaign to nearly $1 billion.

Seeking to play down the importance of fundraising at this stage in the campaign, Republican National Committee Chairman Reince Priebus on Sunday called Obama’s September fundraising “impressive” and said he did not know whether Romney and the RNC will match it. “I think we all understand this race isn’t going to come down to money,” Priebus said on CNN’s “State of the Union,” adding,“This is going to come down to work on the ground.”

From the Obama campaign, senior advisers hit the Sunday shows in an effort to take the sheen off Romney’s performance at the first presidential debate, saying it was rooted in dishonesty.

“Governor Romney had a masterful theatrical performance just this past week, but the underpinnings and foundations of that performance were fundamentally dishonest,” Robert Gibbs said on ABC’s “This Week with George Stephanopoulos.” “Look — he walked away from the central tenet of his economic theory by saying he had no idea what the president was talking about. “

Campaign adviser David Axelrod, on CBS’s “Face The Nation,” said, “I would say that [Romney] was dishonest.”

Aboard Air Force One, the Obama campaign also tried to undercut Romney’s tax proposal. Campaign spokeswoman Jennifer Psaki, using what she called “back-of-the-notecard math,” maintained that the combination of taxes Romney is willing to lower (including income tax rates, the alternative minimum tax, high-income payroll taxes and corporate income tax) add up — with no new off-setting revenues — to $5 trillion in additional debt.

Both candidates are focusing on truthfulness in their latest television ads.

Romney’s campaign unveiled a new ad over the weekend, saying Obama is not telling the truth when he says Romney wants to cut $5 trillion in taxes. The campaign has not said where the ad will run.

Obama’s campaign is running a new ad called “Dishonest,” which says Romney grossly misrepresented his own positions on taxes, as well as Obama’s, during last week’s debate.

On Monday, the president is scheduled to announce the establishment of the Cesar E. Chavez National Monument at the National Chavez Center in Keene, Calif. He is also scheduled to attend two campaign fundraising events in San Francisco. Romney is scheduled to deliver a foreign-policy speech at the Virginia Military Institute in Lexington.

Turque reported from Los Angeles. Kindy reported from Washington.