Democrats could net a seat or two among the state's 27 congressional members, as Republicans David Jolly and Carlos Curbelo would face more difficult fights for re-election while Democratic Congresswoman Gwen Graham's seat became all but a lost cause for her party.
In the state Senate, shifting lines likely wouldn't tip Democrats into the majority but could give them a chance at splitting the chamber down the middle —- if a few bounces went their way —- given a 2016 electorate that was likely to be more diverse than during midterm campaigns that favor the GOP. Based on past voting numbers alone, neither party held a clear-cut majority.
Reality has been more complicated. Going into Tuesday's elections, there might be a little more room for Democrats to gain in the U.S. House, but any whispers of Republicans losing the state Senate majority are essentially gone.
Democrats, as expected, find themselves in a deep hole in the race for Graham's North Florida seat, with the congresswoman months ago dropping re-election plans to consider a bid for governor in 2018. Meanwhile, Jolly is locked in a heated battle with former Gov. Charlie Crist in a Tampa Bay congressional district. And Curbelo is facing former Democratic Congressman Joe Garcia for a South Florida seat that both men have occupied.
But new opportunities have opened up on both sides that could affect the current 17-10 Republican edge in the congressional delegation.
Longtime Republican Congressman John Mica faces a stiff challenge from businesswoman Stephanie Murphy in a Central Florida district the Democratic Congressional Campaign Committee identified earlier this year as "the most competitive" district in Florida.
For Republicans, U.S. Army veteran Brian Mast could take the House seat in northern Palm Beach County and the Treasure Coast being vacated by Democrat Patrick Murphy, who is running for the U.S. Senate. Mast is locked in a race with Randy Perkins, who made his fortune in disaster relief.
Susan MacManus, a political science professor at the University of South Florida, said the four seats most likely to switch hands in the general election —- aside from Graham's —- were those belonging to Jolly, Mica, Curbelo and Murphy. The resulting change might not be a landslide for Democrats.
"On the other hand, it would be a step in the right direction," she said.
Districts were redrawn for this year's elections after lengthy court battles about whether the Legislature had complied with "Fair Districts" standards approved by voters in 2010. The standards were aimed at ending gerrymandering, and voting-rights groups successfully argued that the Legislature did not adequately carry out the requirements.
The legal wrangling resulted in all 40 state Senate seats being up for election this year. But the longstanding Republican majority in the Senate looks safe. With 21 seats needed, there are 16 GOP candidates who face no opposition or token opponents, like write-in candidates or candidates without party affiliation. Democrats have eight such seats. Both parties are favored in a handful more.
Sen. Oscar Braynon, a Miami Gardens Democrats who will lead the party in the Senate after the elections, said Democrats could move from their current 14 members up to somewhere between 16 and 19. That marks a tacit acknowledgment that even the strongest night for Democrats on Tuesday will almost certainly not cost Republicans the majority.
Still, Braynon credits redistricting with creating more competitive seats than in a traditional Florida election.
"I think it's been a different cycle than any cycle we've ever seen," Braynon said.
He said gains this year could lead to a Senate majority in the future.
"I think that this is the foundation of that," Braynon said. "These maps do not lend themselves to a Republican domination of the Senate."
Redistricting has changed some candidates' calculations. Former Sen. Rod Smith, a Democrat from Alachua, decided to enter the race for Senate District 8 in North Florida in large part because of the redrawn lines.
"I wouldn't have run in a seat that I didn't think was attainable. I wouldn't have run in a seat that I didn't think was competitive," Smith said. "I knew it would be a difficult seat, and it will be a difficult seat, because the numbers are very close."
In 2012, President Barack Obama carried the district by 1.4 percentage points. Smith's Republican opponent, state Rep. Keith Perry of Gainesville, suggested that the map the courts adopted based on suggestions from voting-rights groups favors Smith.
"This map, I believe, was drawn for my opponent," Perry said. " ... That's kind of irrelevant. The courts accepted it and that's where we are. You just run a race and you talk to people and work to get elected."
When courts redrew districts for Florida's congressional delegation and the state Senate, assumptions quickly poured in.