Republicans couldn’t be happier this week about their good fortunes in Florida.

Just days before a filing deadline, Sen. Marco Rubio decided to reverse his long-running pledge not to seek reelection, greatly improving the GOP’s chances for retaining his seat. Meanwhile, his best-financed potential Democratic opponent, Rep. Patrick Murphy, took a serious bruising from an investigative report done by a Miami TV station that concluded he had exaggerated key details of his professional resume. This has national Republican operatives more confident than at any point this election year that they can manage to retain the Senate majority.

Fellow Republicans have smoothed Rubio’s return to Senate since he announced his decision Wednesday. Three credible GOP candidates left the race, and a fourth — businessman and former Special Operations officer Todd Wilcox — announced Friday he would drop out and endorse Rubio’s re-election bid: “I respect his grasp of the challenges we face and I appreciate the reality that he, as the incumbent, is best positioned to defeat either Patrick Murphy or Alan Grayson in November,” he said in a statement.

But Rubio still faces a major obstacle in the Aug. 30 Republican primary, and his name is Carlos Beruff. Beruff is a 58-year-old real estate developer who, like Rubio, is the son of Cuban refugees who settled in south Florida. He has been a major supporter of Republican politicians in Florida and is now making his maiden run for office as an outsider with a decidedly Trumpian bent. “Put America First,” his yard signs read. And he is making no plans whatsoever to drop out of the primary race.

“I will commit the resources that are necessary, and I will be in this race for the next 70 days that are remaining, and I believe that the Florida voters will make the right decision,” Beruff said in a phone interview Wednesday. “They will see it’s time to send people to Washington who don’t need the job and don’t need the promotion.”

What could make Beruff more than an annoyance to Rubio is his willingness to self-finance, his embrace of outsider politics in the year of Donald Trump, and his connections to Florida’s Republican governor, Rick Scott, who rode an outsider message (and tens of millions of his own dollars) into statewide office.

Scott on Thursday declined to fall in line behind Rubio, announcing in a statement that Florida voters “deserve the opportunity to consider [Beruff’s] candidacy alongside Senator Rubio and make their own decision.” Also notable: The political team that helped Scott win two terms as governor are now in Beruff’s camp.

Beruff has signaled he will pull no punches when it comes to Rubio. On Wednesday, hours after news of Rubio’s decision broke, Beruff dismissed Rubio as a “political hack.”

“His word means nothing, and that’s what politicians do — they lie, and they break promises,” he said. “And I think that the Florida voters are much smarter than that, and I’m willing to bet my money to find out.”

And he also leveled the sort of attacks that Democrats are already using to bedevil Rubio. “He is just positioning himself to get another shot as the election for president, which obviously he failed miserably,” he said. “People are smart. He hasn’t been representing Florida voters for six years. He hasn’t come back to the counties and the people who voted him into office, and he hasn’t done the job that 2.6 million Floridians hired him to do. … That’s the difference between people that run businesses and politicians. We don’t talk as much, we just do things, and he has done nothing in his six years as a senator except speak.”

Now Beruff’s bluster may only get him so far. A recent survey from the Saint Leo University Polling Institute showed half of lively primary voters backing Rubio, with Beruff garnering less than 5 percent in a splintered field. And there is no evidence that he will be willing to self-fund to the tune of $73 million — which is what Scott spent to get elected to statewide office in 2010.

But Berfuff said this week he will “will commit the resources that are necessary” — at least $20 million, according to Florida press reports — and that it still significant in a relatively low-turnout summer primary. And with Wilcox now out of the race, Beruff can claim to be the consensus outsider candidate. That could be enough to force Rubio and allied outside groups to spend many millions of dollars to beat Beruff before they can sink their fangs into Murphy or Grayson.

Rubio previewed his attacks on Beruff this week in an interview with Politico, noting Beruff’s support for former GOP Gov. Charlie Crist, who ran against Rubio as an independent in 2010 and is now running for the House as a Democrat. “He’ll have to answer for that,” Rubio said.

Said Beruff on Wednesday, “It’s a lie. When Charlie Crist went independent, I no longer supported him. Just track the money. And the second thing is, at the end of the day, he should look in the mirror because he has turned into Charlie Crist.”

Rubio has also signaled he will distance himself from Trump — after losing the Florida presidential primary to him by nearly 20 percentage points — and Beruff suggested he would be able to take advantage of that divide.

“Florida voters, and voters nationally, have spoken as to who they think their candidate is, and anybody who wants to try to derail the representation of those voters is making a huge mistake,” Beruff said. “They are not going to succumb to the Washington politicians who are telling them who they are supposed to vote for — in the Senate race or in the presidential race, either one.”