The jousting came ahead of Friday's monthly jobs report, an important barometer for the economy. Economists forecast that U.S. employers added 100,000 jobs in July. That would be slightly better than the 75,000-a-month average from April through June but still below the healthy 226,000 average in the first three months of the year.
It also followed more stalemate in Congress over taxes. On Wednesday, the Republican-controlled House approved a universal extension of Bush-era tax cuts. The vote came a week after the Democratic-controlled Senate voted for Obama's plan to continue current tax rates only for households earning less than $250,000 and for individuals under $200,000.
With the tax issue dominating the debate, Obama has tried to cast Romney as a promoter of tax cuts for the wealthiest Americans he is one of them at the expense of popular tax breaks for typical families. For the second straight day, Obama turned to a study by economists at the Tax Policy Center and the Brookings Institution, saying Romney's plan would lead to a tax increase of more than $2,000 a year for an average family with children.
"They have tried to sell us this trickle-down tax cut fairy dust before," Obama said in Winter Park, Fla., outside Orlando. "And guess what? It didn't work then and it won't work now."
To emphasize the point, Obama's campaign released a new TV ad going after Romney, a millionaire many times over, for paying about 14 percent of his 2010 income in taxes. "He pays less, you pay more," the ad says.
Romney's campaign has dismissed the report, challenging its impartiality and methodology. Eric Fehrnstrom, a senior Romney adviser called the report "a joke" during a conference call with reporters.
Romney backed his Colorado appearance with a new spot timed to the president's Florida appearance and calling him a "disappointment" because Florida's economic picture hasn't improved under his watch.
Romney's response ad shows footage of Obama giving a speech in 2008 and lamenting the state of Florida's economy. The spot notes that Florida still suffers from high unemployment, record home foreclosures and more of the state's residents living in poverty. "Barack Obama: What a disappointment," the ad says.
In Colorado, Romney also vowed to make North America energy independent in eight years, saying he would emphasize drilling on public lands, coal production and the completion of an oil pipeline, but did not offer any other specifics. He said his proposals would create 12 million jobs during his term but offered no details on how that would come about.
Later in the day, Romney was appearing with 10 Republican governors, including some mentioned as potential running mates, at an event near Aspen. The grouping was teasing speculation about Romney's vice presidential pick, as some of the attendees New Jersey's Chris Christie, Louisiana's Bobby Jindal, South Carolina's Nikki Haley and Virginia's Bob McDonnell have been mentioned as possible Romney running mates. Sen. Rob Portman of Ohio and former Minnesota Gov. Tim Pawlenty, the two most often mentioned possibilities, were not expected to attend.
After the stop in Florida, Obama was headed to Leesburg, Va., in the nation's wealthiest county, near Washington, D.C. Obama carried Loudoun County in 2008, the first time a Democratic presidential candidate won there in four decades.
Obama was expected to follow Romney's Colorado appearance with a visit of his own to the state next week, followed by stops in Iowa the week after. Romney was launching a multistate bus tour late next week, with stops planned in Virginia, North Carolina and Florida, among other states.