Four years later, Republican Donald Trump defeated Democratic presidential nominee Hillary Clinton in Duval by just 6,434 votes —- then went on to carry Florida while winning the White House in one of the most stunning presidential victories in decades.
Trump's win in Florida reshaped, at least for a night, many of the geographic notions of how presidential elections are won in the state. In Miami-Dade, Orange and Broward counties, Clinton increased Democratic performance by tens of thousands of votes over Obama's showing four years ago. She not only cut into Trump's edge in Duval, but reduced his advantage in suburban Seminole County by nearly three-quarters.
It wasn't enough, though, to hold back a tidal wave of votes in rural and blue-collar counties that decisively rejected Clinton. In Pasco County, voters who had given Romney a 6.6 percentage-point victory in 2012 backed Trump by nearly 21.6 points this year. In Volusia County, which Romney won by just over a percentage point four years ago, Trump cruised to a 13-point victory.
Trump improved the Republican margin of victory or defeat in the presidential race by more than 10 percentage points in 22 counties. The equivalent number of counties for Clinton was zero.
"White working-class areas, just like we saw in the rest of the nation, just rebelled against her," said Matt Isbell, a Democratic analyst based in Tallahassee.
Isbell said white voters in more suburban areas, like Seminole County, were buffered from some of the economic forces that swept Trump to victory in working-class areas like Pasco County. That made those suburban voters less enthusiastic about going with a controversial real-estate mogul dedicated to shaking up the establishment.
"They're doing fine," he said of the suburban voters. "They see no reason to vote for somebody like Donald Trump."
That rebellion wiped out what might have given Democrats the view that they were winning heading into Tuesday. The party aggressively banked votes that were supposed to build a seawall, but proved ineffective. Across 10 counties, Clinton added 197,000 votes compared to Obama's performance against Romney four years ago.
Those gains were almost wiped out by Trump's win in his seven best counties, based on the swing in the raw number of votes, where he gained almost 192,000. Nowhere was that more clear than in and around the western end of the I-4 corridor. In addition to winning Pasco County, he flipped Pinellas County from Democratic blue to Republican red and crushed Clinton in Polk County, more than doubling Romney's margin.
Democrats' vaunted edge among African-American and Latino voters didn't salvage the race. Isbell said changes in votes by working-class whites canceled out many of those gains.
"Democrats cannot just afford to count on the non-white vote and get killed with white people," he said.
And while Clinton did better in some suburban areas, the defections to the Democrat from wealthier white voters who backed the Republican Party in the past appear to have been less widespread than expected.
"Republicans came home to Trump," said Carol Weissert, a political-science professor at Florida State University. "If you look at the white numbers, even the white college-educated numbers, they were much higher for Trump than we had thought. Particularly, the college-educated women."
Brian Hughes, a Republican consultant, said Trump's unconventional strategic moves helped him run up vote totals in areas that traditionally haven't been a major priority for statewide candidates. Trump visited Tallahassee in the closing weeks of the campaign, part of a push into Northwest Florida that some observers saw as wasted effort given Tallahassee's liberal bent and the already-strong Republican performance across the Panhandle.
Clinton improved her margins slightly in Leon County, where Tallahassee is located, but lost ground in nearby areas.
"I think, strategically, it's just that (the Trump campaign) did everything they could to demonstrate they wouldn't take anything for granted, against them or for them," Hughes said.
But Hughes pushed back against the idea that race was a decisive factor in Trump voting. He pointed to exit polls suggesting that Trump might have done better, at least marginally, with Latino voters than Romney did in 2012 —- meaning the sense of disenfranchisement cut across ethnic lines.
"The Trump victory just says to incumbent and establishment types: Pay attention to the people you say you want to represent," he said. "Or ignore them at your own peril."
News Service of Florida Assignment Manager Tom Urban contributed to this report.
In 2012, then-GOP presidential nominee Mitt Romney beat President Barack Obama in Duval County, a crucial area for Republicans running in Florida, by 14,878 votes. Romney would lose Florida and the presidential election.