WASHINGTON — President Barack Obama courts voters in Florida on Thursday, opening a two-day campaign swing in a battleground state that could decide this year's election. If Obama can win Florida, as he did in 2008, Republican challenger Mitt Romney would have a difficult time blocking the president's return to the White House. The US presidential elections are not won according to the popular vote nationally but in state-by-state contests. Obama and Romney are in one of the closest presidential contests in recent memory. What would be a normal advantage for an incumbent president has been diminished by voter concerns over the sluggish economic recovery and 8.2 percent unemployment. The race promises to be even closer in Florida. Obama aides said that since 1992, voters in the state have cast more than 32.5 million votes during the past five presidential elections, and only a total of 57,000 votes have separated the two parties in those campaigns. “Florida's always a close state, and we don't expect that to change between now and November," said Obama spokesman Ben LaBolt. Themes that have dominated the campaign should show up again during Thursday's events. Obama has repeatedly criticized the private equity firm Romney co-founded, Bain Capital, arguing that it promoted the outsourcing of jobs to countries like China and India. And Democrats want Romney to make public past tax returns, noting that the one year for which he has released returns showed investments and offshore accounts in Switzerland and the Cayman Islands. Several Republicans have joined in the call for more transparency, including Texas Gov. Rick Perry, who challenged Romney for the party nomination earlier this year. In an interview aired Thursday on an Ohio television station, Romney said one reason not to release more of his returns was that “the Democratic party and the opposition has all these people that comb through and try and find anything they can to distract from the issues people care about, oftentimes in a dishonest way." — AP