He reached for some Ronald Reagan-like optimism in hard times, telling his audience that much about America is essentially right.
"When our opponents say this nation is in decline they are dead wrong," he said. "This is America. We still have the best workers in the world and the best entrepreneurs in the world. We've got the best scientists and the best researchers. We've got the best colleges and the best universities."
He went on: "We are a young nation with the greatest diversity of talent and ingenuity from every corner of the globe so no matter what the naysayers may say for political reasons, no matter how dark they try to make everything look, there's not a country on Earth that wouldn't gladly trade places with the United States of America."
Days earlier, GOP vice presidential candidate Paul Ryan noted that the national debt was reported to have passed $16 trillion on the first day of the Democratic convention. "That's a country in decline," Ryan said. Unemployment remains stubbornly high, clocking in at 8.1 percent on Friday and keeping joblessness and economic weakness on the boil as top campaign issues.
Romney drew cheers in a Navy town when he pledged to strengthen the armed forces and roll back future defense cuts that he blamed on Obama but were negotiated between the president and congressional Republican leaders.
"We must have a military second to none," he told the Virginia Beach rally. "I will maintain our military commitment." He also plans to expand the naval fleet.
Reciting the Pledge of Allegiance, Romney went through it phrase by phrase to suggest Obama has fallen short of its promise in a nation with painfully high unemployment, millions more on food stamps, and one in six people in poverty. "How can a nation so prosperous stand by with such a national tragedy?" he asked. "That is not 'justice for all.'"
His answer: "We're going to have to get a new president."
Obama opened a two-day bus tour in Florida, campaigning in a state with the highest elderly population and an unemployment rate of 8.8 percent, higher than the national average.
As both candidates enter the sprint to the election, Romney is casting Obama as an inept steward of the nation's post-recession recovery. It's a portrayal Obama has been fighting for months as the unemployment rate sticks stubbornly above 8 percent.
On Friday, the government reported that employers added just 96,000 jobs in August and that, aided by frustrated job hunters giving up, the jobless rate dropped only marginally from 8.3 percent the month before.
Obama is countering by presenting himself as a champion of the middle class and by repeatedly decrying Romney's economic remedies as failed throwbacks that would further endanger the economy.
But Obama is also eager to turn the debate away from the economy and on to issues that favor Democrats. Obama repeatedly reminds audiences that Romney's running mate has proposed to overhaul Medicare, the government health program for older Americans, with a voucher-like system that could cost beneficiaries more out of their pocket.
Obama's team says the Medicare argument could help attract undecided voters approaching retirement age, more so than elderly voters whose political views are already set.
Obama's visit to Florida is his first since Romney and the GOP held their convention in Tampa last month. With 29 electoral votes, the state is a lynchpin in both candidates' strategies for winning the election.
Romney and Obama are deadlocked in Virginia, where the Democrat is strong in the northern suburbs of Washington, D.C., and Romney does better in the south and rural areas.
Romney sees working-class white voters, who have at times voted for moderate Democrats such as Sen. Mark Warner, as ripe for picking. Polls suggest those voters prefer Romney over Obama. Romney was visiting a NASCAR race in Richmond later Saturday, a nod to this potentially pivotal voting bloc in Virginia.
Deep spending cuts, including to the armed forces, are to begin automatically next year unless Congress negotiates a debt-reduction package. Obama has opposed the depth of the cuts but has said Republicans need to adopt a plan that includes increases in revenue.
Beaumont reported from Virginia Beach, Va. Associated Press writer Matthew Daly in Columbus, Ohio, contributed to this report.