APOPKA, Fla. (AP) — President Barack Obama and Republican Mitt Romney have this in common when it comes to Florida: They’re both worried about the biggest election battleground prize.

The president has an edge here, but Democrats fear the advantage may be fleeting and fret about Florida’s undecided voters. They’re also nervous about legal battles over state voter laws that could cut into Obama’s support among minorities.

Republicans are concerned that Romney hasn’t closed the deal in a state hampered by joblessness and home foreclosures, even though he’s cast himself as the economic fixer and, along with his allies, has spent significant money and time here.

The state is especially critical for Romney.

With his paths limited toward the 270 electoral votes needed to win the White House, Romney’s chances are far more difficult if he doesn’t claim Florida’s enormous cache of 29. That explains why he’s starting to pour even more money into television commercials here now that he has access to general election funds. Both campaigns expect Republicans to outspend Democrats on the airwaves in the final weeks of the race in a state that already has seen each side spend roughly $60 million on TV and radio ads.

The situation in Florida — and the campaigns’ anxieties about it — reflects the overall state of the presidential race.

A new smattering of polls shows Obama ahead by several percentage points in key states including Florida, Ohio and Virginia, as well as nationally. The clock is ticking toward November, Obama clearly has momentum on his side and Romney faces dwindling opportunities to change the race’s trajectory.

Without Florida, Romney would have to win all of the states that are leaning his way, as well as all of the others that Obama won four years ago but now are too close to call — Ohio, Virginia, Iowa, Colorado, Nevada and New Hampshire — and still pick up two more electoral votes elsewhere, in states that are even more difficult. The uncertainty of Florida partly explains why Romney now is making a play for Wisconsin. That state, which offers 10 electoral votes, has voted for Democrats for decades, but the GOP has seen down-ballot success there lately and Romney running mate Paul Ryan lives there.

Obama already has far more states — and, thus, electoral votes — in his likely-winners column. Because of that edge, he can hold the White House without Florida as long as he wins most of the other toss-up states. His standing has suffered here along with the state’s economy, four years after he won the state by cobbling together a coalition of Hispanics, African-Americans and independents to go with other Democrats.

This year, undecided voters, and those not entirely sold on their candidates, may well tip the balance here. Few seem hot on either contender. And most say the economy is Issue No. 1 in a state whose 8.8 percent unemployment rate is among the highest in the nation, as is its foreclosure rate.

Kathy Belcher, a Democrat from Apopka, is leaning toward Obama but says she would be willing to give Romney a chance if he offered more details on the economy and health care.

‘‘It seems with Obama, people are getting a handout,’’ Belcher said. So, she added, she'd considering voting for Romney if he could assure her that won’t happen under him. ‘‘But that hasn’t happened.’’

Donna Sprenkle, a registered Republican from Apopka, plans to vote for Romney — reluctantly. She doesn’t think he’s explained well enough how he would fix the economy.

‘‘I know somebody just can’t overnight bring it back,’’ Sprenkle said.

These are among the persuadable voters Obama, Romney and their top surrogates are courting as they make weekly campaign stops in Florida. Both candidates are expected to visit next week as the latest public poll — an NBC News/Wall Street Journal/Marist Poll released Thursday — shows Obama with a 49 percent to 44 percent advantage over Romney.

‘‘"It should come as no surprise that Mitt Romney and Paul Ryan are having trouble in Florida,’’ said Rep. Debbie Wasserman Schultz of Florida, chairwoman of the Democratic National Committee. ‘‘We already tried the Romney-Ryan economic scheme that trickles from the top down.’’