Ground game matters. Organization matters.

That’s the biggest take-away from President Barack Obama’s strong showing Tuesday in Florida, a state with such high unemployment and home-foreclosure rates that it was primed for a Republican win.

But, with thousands of votes still out Tuesday night, Obama appeared close to winning the nation’s largest battleground state, thanks to a mammoth grass-roots campaign. It may have killed Mitt Romney’s chance of unseating the incumbent.

Obama led Romney 50-49 percent in Florida, according to Edison Research’s exit poll that exactly mirrored the results of the actual vote as of Tuesday night.

With voters casting ballots well into the night, the final tally for Florida won’t be clear until at least Wednesday afternoon, when Miami-Dade County plans to announce its final results. More than 18,000 absentee ballots turned in Tuesday have yet to be counted.

The race could be close enough to trigger a recount — unless it is waived by Romney, who lost the overall election to the president.

Obama’s strength: liberal Southeast Florida, where early vote returns showed the president nursing a double-digit lead. Romney did well in conservative North Florida.

For the first time ever, a Democratic presidential candidate won absentee ballots — typically a Republican strength — in Miami-Dade County, with Obama eking out a 382-vote margin. That was a leading indicator of Obama’s strong grassroots campaign, which involved 200,000 unpaid volunteers who helped register 320,000 new voters this year.

Obama won big with the fastest-growing segment of the electorate: Hispanic voters, who voted for the Democrat, 60-39 percent, the exit poll showed. That’s better than Obama did in 2008.

Obama’s Hispanic-vote margin came despite a massive Hispanic-outreach effort by Romney, who struggled at times in the general election because of the hardline immigration policies he espoused during the Republican primary. Obama won big in Osceola and Orange counties, home to a burgeoning Democratic-leaning Puerto Rican population that’s starting to counterbalance Cuban-American Republicans in Southeast Florida.

Obama’s Hispanic outreach effort was so robust that he planted a field office — one of more than 100 in Florida — in the once-Republican stronghold of Little Havana.

“I have faith. I have faith in him,” independent voter Sandy Basham, 39, said Election Day when she cast her ballot. “He just needs more time.”

Obama carried independents, 50-48 percent, the exit poll showed. Independents are the key to winning Florida, a nearly deadlocked state. Obama won outsized black-voter support, but lost non-Hispanic whites by double digits.

Heading into Election Day, Democrats had cast 167,000 more early votes statewide than Republicans. But the Romney campaign denied it had much significance. They pointed out that Obama was doing worse than he did in 2008, when he won Florida by less than 3 percentage points.

But Obama 2012 wasn’t running against Obama 2008. He ran against Romney 2012. And it looks like the president won that contest.

The final results are still in doubt and the margin will be close either way. Late Tuesday, the margin was so close that the winner could be decided by Libertarian Party candidate Gary Johnson, who had more than 41,000 votes.