Florida could be a swing state this year in more ways than one.

While the state plays a famously decisive role in presidential races, its voters are poised to be power-brokers in the 2016 battle for control of the Senate – as the seat being left by ex-presidential candidate Marco Rubio becomes fiercely contested.   

The seat is one of several Democrats hope to flip in November in their quest to regain the majority. But first, they’ll have to slog through what is becoming a raucous primary fight between the combative and controversial Rep. Alan Grayson, who is facing an ethics inquiry in D.C., and Rep. Patrick Murphy.

And with Grayson picking up steam in the primary, Democratic leaders may now be worried that if he wins the nomination, it could hurt their chances of picking up the seat in the fall. None other than President Obama and Vice President Biden already have endorsed Murphy in the race – as recent polling shows Murphy doing far better than Grayson in general election match-ups against Republicans.

For that reason, some Republicans appear to be rooting for Grayson to pull it out.

“It would be great to have a Hillary Clinton and an Alan Grayson on the ticket. It would be a dream race to have as chairman of the Republican Party of Florida,” Blaise Ingoglia, Florida GOP chairman, told FoxNews.com.

Murphy is turning up the heat, though, as he tries to blunt Grayson’s primary momentum.

The congressman called on Grayson to quit the House this week after the Office of Congressional Ethics issued a report saying “there is substantial reason to believe” Grayson violated the law and House rules with various activities, including apparently lending his name to a hedge fund and getting compensated by the fund, according to the report.

“The [ethics] committee has voted to keep the investigation of Congressman Alan Grayson going because he broke the law,” Murphy said in a conference call. “He broke the law to make money with an offshore hedge fund. It’s that simple.”

Grayson responded that he did nothing wrong, while his campaign said Murphy is trying to gain an edge in polling by shifting the focus of the race.

David Damron, Grayson’s communications director, said Murphy “needs to stop wasting the time of voters and taxpayers with his political-smear campaign and start talking about the issues.”

He said: “Rep. Grayson wants to expand Social Security and Medicare, and ensure that everyone can see a doctor and make a livable wage at $15 an hour. That’s what this race is about.”

The race itself evolved because Rubio was not allowed by Florida law to seek re-election while running for the Republican presidential nomination. Rubio has since suspended his presidential campaign, after failing to make up ground against candidates Donald Trump and Ted Cruz, but still has to leave office.

On the Republican side, the race is dominated by Rep. David Jolly, Rep. Ron DeSantis and Lt. Gov. Carlos Lopez-Cantera, among other lower-polling candidates. But all the attention is on the Democratic side right now.

At stake in this and other races is control of the Senate, which Republicans run with a 54-46 seat majority. According to Sabato’s Crystal Ball at the University of Virginia, Florida’s is one of five toss-up seats this cycle.

Kevin Cate, a Democratic strategist based in Tallahassee, said Murphy has the temperament needed to mount a successful general election campaign against the Republicans.

But first, Murphy would have to get through the primary.

Cate said many in the party see Grayson as someone with a “Trump-like” campaigning style, which has its plusses and minuses, including the risk of not demonstrating a demeanor consistent with the top of the Democratic ticket.

“Grayson knows how to draw media attention, whether it is good press or bad press,” he said.

Max Steele, communications director of the Florida Democratic Party, told FoxNews.com he is confident either of the current Democratic candidates would be “formidable” in a general election.

Plus, he said with Trump or Cruz at the top of the Republican presidential ticket, he’s confident a Democrat can win in the Florida Senate race.

Ingoglia said even with all the ethical issues, Grayson is in a position to give Murphy a run for his money – despite, or perhaps because of, his establishment support.

“People are very unhappy with handpicked candidates. That’s what Patrick Murphy is, a handpicked candidate by the Democratic establishment. He’s the flavor of the day,” he said.

Ingoglia, meanwhile, touted the diversity of the Republican field, saying any of the candidates running for the Republican nomination are capable of not only winning in the general election, but also serving as senator.

On the Republican side, the latest Public Policy Polling survey released last month showed Jolly leading the field with 26 percent. DeSantis followed with 14 percent and Lopez-Cantera came in third with 11 percent. There is still time for the dynamics to change before the Aug. 30 primary, and 47 percent of Republicans surveyed said they currently have no preference for any candidate.

On the Democratic side, Grayson led Murphy, 33-22 percent, with many still undecided.

The poll of 464 likely GOP voters and 388 likely Democratic voters was taken Feb. 24-25. The GOP poll had a margin of error of 4.6 percentage points; the Democratic poll had a margin of error of 5 percentage points.